8yo son -- crazy burps

Hi,
Id appreciate some assistance choosing *A* remedy for my 8 yo son.

*****As a preface, please do not respond by suggesting I go to a medical doctor, or any such wasted words.
You do not know what my family is doing beyond the scope of this post, which is specifically for the purpose of requesting discussion on homeopathic remedies; nor is it your business or responsibility to butt in any further than the specific questions Ive presented for discussion.
I realize this is a defensive preface, however, Ive dealt enough on this forum to know what kinds of responses occur, and Im just attempting to cut out some wasted time. Please only discuss homeopathic remedy options. Please only respond in this context. Thank you. ******


His primary symptoms are:

** very large and frequent burping almost immediately after eating or drinking literally anything. Often while eating he will pause and say his stomach hurts very bad, and then a few seconds later, a big burp, and then he says, never mind, I just needed to burp.

** frequent small burps, seemingly at will.

** constipation that comes and goes. We push lots of plain water (he really enjoys carbonated water, but that makes him pretty acidic so we greatly limit those), ....and every few days or so we give psyllium husk and a little aloe juice, and occasionally a magnesium supplement, which does help.
He has had a few bouts of feeling very sick and vomiting nearly undigested food (the last occurrence of this was several weeks ago; we were, at the time, unaware that he was constipated and have since figured out this is the cause of the nausea/stomach pain/vomiting -- hence the psyllium, aloe & mg).
He does experience a bit of car-sickness when he moved from the passenger side seat to the middle seat in the back; he says he still experiences a tiny bit on the passenger side, but doesnt appear to be bothered by it anymore.

** He occasionally has growing pains, which appear to be sudden stabbing or cramping, mostly occurring in his legs.

** He has an odd habit of rolling his neck, where he stretches his head all the way backward, rolling from shoulder to shoulder, and theres a single pop sound that happens. He says its annoying but it doesnt cause pain or anything. And its different than cracking the joints.

** He is a very rowdy, silly kid, and also very sweet and with a sensitive conscience. Not overly sensitive, just emotionally intuitive and responsive. Tenderhearted, in a good way. He is very intellectual, logical, and loves to debate/argue (not so great LOL) always wants to know the reasons for things, and then tries to figure out how to work around the reasons.

He feels the need to explain situations thoroughly, and must be allowed to fully finish his explanation, or else he feels completely stifled and frustrated.

Hes very quick at math; he was an early reader, practically taught himself around the age of 5 1/2, and is now reading at least at a 5th or 6th grade level, if not higher.


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Background:

We are a very healthy, clean-living family. We avoid junk food, highly processed foods; I make most everything from scratch. We avoid conventional dairy products, conventional wheat, and soy due to commercial production contamination.
Our diets are fairly balanced in comparison to the average American diet. Lots of fresh fruits and vegetables, some we grow ourselves; healthful meats with good fat ratios (animal fats are good for you!) and we avoid vegetable/seed oils, except for Avocado.
Myself and both of my kids do have MTHFR genetic mutations, and what I believe to be ADHD and Hypermobile Ehlers Danlos. We have not sought official diagnosis of these because that is extremely expensive, and the symptoms are quite manageable.

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Please let me know if there is anything else in particular that would help in suggesting some remedy differentials.

Please *do not* suggest a multi-remedy course of treatment, as I prefer to try one at a time and then assess its effectiveness. Thank you.