Seeking Help for Behavior Problems and Constipation in a Toddler

My son is 2.5 years old, he's always been a pretty active kid, he's always needed a lot of attention, and he's struggled with constipation since he started solid food, though with diet his constipation has been pretty well under control. But over the past month or so everything has gone down hill and he is completely out of control. Our biggest problem is that he will not stop throwing things. He will throw hard things at me and my husband several times a day sometimes because of not getting his way or something like that that upsets him but sometimes for no apparent reason at all. He'll do all this throwing with a straight face, not crying or screaming like it's part of a tantrum and the only way to get him to stop is to take him to a room where there's nothing to throw and wait for him to calm down, but even then he might go right back to throwing as soon as he gets hold of an object. He no longer is very interested in playing with his toys aside from throwing them. And he demands my attention pretty much 100% of the time and won't let me take even a few minutes to clean or prepare a meal without starting to throw things at me. He's in constant motion during his waking hours and can't even sit in a chair to eat. His constipation is pretty bad now and he's only having a bowl movement about once a week. I'm hoping homeopathy can help him.