My condition - digestive problems, mainly

I apologise for writing so much, but I think that any partial description of my condition wouldn’t provide a good enough perspective to suggest a treatment. I would be extremely grateful if someone read it and expressed their opinion despite the length and complicity.
A heartfelt thank you to anyone who decides to!
For some time, about two years if my memory serves, I've been experiencing symptoms related to digesting; it started with a period of constipation and a feeling of abdominal fullness, which caused some discomfort, but no pain. It was later accompanied by flatulence and frequent (sometimes very frequent, if not ceaseless) stomach bloating and a need to relieve the gas. I started to have an urgent need to defecate each morning, sometimes to the point of worrying about incontinence. It was then that I started to smoke, give or take, though I think it had started before. It continued, sometimes worsening but otherwise pretty stable, for a year or so, when occasional pain before passing stool appeared - one localised not directly in the rectal area, but as if higher and often on the left side of the navel. These occurrences are marked with acute yet not extremely severe pain and either go away after defecation (in most, almost all cases), or last up to a few minutes afterwards. It feels as if the stool, having started to move down the colon (I mentioned that the need is urgent and comes quickly, usually initiated by eating and smoking) irritated something on its way and when it's left behind the very act of passing is rather painless, save for occasional irritations from hard stools. Defecation gives relief and in almost all cases I feel well except for a little fatigue, which passes though. I had a few episodes of pains localised more or less in this area but of a slightly different nature - it's like a cramp-like sensation in the anus or broader, the scrotum area. It first appeared after defecation (and I can remember a few occurrences when I was a child)and then, in its most painful attack yet, after ejaculation. I remember it was so unexpected and acute that for the time it lasted (half an hour, give or take) I couldn't do anything or thing about anything else. It's got me seriously worried then, I remember, and may well have returned during defecation. What I thought of at the time was prostatitis, because I had noticed some whitish bumps in my semen a few days earlier and it made sense altogether; I had a homeopathic medicine my doctor prescribed for some other problems (I had had a pain attack of unknown nature in my chest a few weeks earlier and had some problems breathing since) - Traumeel, which is used also for treating inflammations, and it apparently helped, i.e. I haven't had such severe attacks since and my semen was clear.
Presently what I find most disturbing are the stomach symptoms - very frequent belching, which often makes me embarrassed while talking and is especially troublesome after eating or drinking, even very small amounts; flatulence appears too, but not as bad as it once was, I think. I don't have nausea often and my appetite is fine - I can eat everything and the symptoms seem not to rely on what I eat. The last few weeks have been worse, especially a week or so ago when the morning need to defecate became stronger and would appear earlier than normally, even before I ate or smoked. It also returned a few times a day and sometimes felt just like cramps, while I couldn't pass hardly any stool - this has got almost normal by now, but the stomach symptoms have got worse instead. I also had a sore throat for two weeks or so and experience constant problems with my sinuses - have difficulties breathing through the nose and feel as if mucus was constantly passing to my throat. What may be important, I think, and what may well be at least a partial cause of all this, is that I'm quite nervous and the last year or two seem to have effected me quite seriously in this matter. I easily get stressed or worried and the most prominent physical symptom was that I started to feel a strange sensation of blood rushing up to my head, which felt as if bloating, even on the verge of exploding. This appeared sometimes unexpectedly, sometimes preceded by some physical excursion and made me afraid of going out. Since I was a child I'm also having recurring episodes of derealisiation - a feeling of not being sure what I perceive is what actually happens, if I am where I think I am and so on. Not severe, not disturbing everyday activities and certainly not noticed by anyone else or impairing my intellect for a long time, it is unpleasant and worrying though, if not frequent lately. The point when all the above problems reached their culmination was this winter - I was stressed, isolated from people, tired, lacked physical activity due to the fear to go out, would have no motivation to work and so forth, which finally resulted in the chest pain attack I mentioned above. It was the straw that broke camel's neck and I decided to seek medical help; after having some tests done (EKG, X-rays, blood), which all didn't indicate anything, I consulted a homeopath (a random choice, there are not many where I live), whose first reaction to what I told him was suggesting the kidneys which were allegedly to weak, causing the cold limbs, problems breathing, a feeling of not being 'at home' in my body and emotional destabilisation. He wasn't much concerned with the digestive symptoms and said only that the kidneys, regulating everything that has to do with air in the body, cause these flatulence and stomach gas problems (he combines homeopathy with anthroposophical medicine) and prescribed hot compresses and cooper ointment, Dr Bachs flower therapy for emotional problems, Traumeel and Berberis for the chest problems that could be neuralgia. The chest pains are really gone, but the other symptoms were not much affected. Later on I consulted him again and this time stressed them more, which resulted in him prescribing me some herbal medicine for the kidneys, Berberis e fructibus for the sinuses and the air passages and a homeopathic mixture for nerves (Lehning L72 - works magically!), but still nothing for my digestive problems which cause so much distress. I know that what I do is not the most rational choice - I probably should have had endoscopy and colonoscopy done a long time ago to rule many serious things out (my family has a history of colon problems - my grandfather died of colon cancer and his brothers, having learned on his misery, have multiple polyps removed during each colonoscopy they undergo), but I can't force myself to do it. Quitting smoking would be a good idea too, but this won't happen - what I'm working on is reducing the number I smoke. I wonder if there is an effective way to help reduce the toxic effects smoking has on the body? And so I'd like to hear a second opinion here since I can't afford one anywhere else. Is this possible the kidneys are the main problem? What may indicate that there is at least something wrong with my urinary tract is that I’ve been feeling bladder pain each morning and some episodes of lower back pain on the sides for the last few weeks. I’ve had blood and urinary tests done few days ago, which both didn’t indicate anything wrong, save for a slightly lower creatinine level. From the little research I've done Aloe and Sulphur seem a good choice for my digestive problems, but I can't tell for sure, of course.
To sum it up, my problems include:
- abdominal pain before defecation; acute, as if something was irritated on the BM's way down; usually on the left side of the navel. Defecation brings relief.
- fatigue, tiredness, lack of motivation, laziness, stress.
- problems with breathing, usually in the morning; mucus in throat, as if passing from the sinuses, blocked nose; “bloating” head, as if from blood filling it suddenly, dizziness.
- bladder pain in the morning, lower back pain on the sides,
- flatulence and very frequent belching, heartburn;
- skin sensitivity, as if from a fever.
- episodes of scrotum cramp-like pain after ejaculation or defecation (haven’t experienced it since a month or two, but during last two years it was occurring regularly).