Walking issue

I have heard rumours that chewing from one side of your jaw consistently can bugger your walking. For some reason i can no longer walk or run properly and i get incredible pains some times when i try and run or walk. I am also getting this strange pattern where my body twitches etc by itself not all the time but here and there. Also i seem not to be able to gain any muscle either while using the correct work outs for a sustained period of time (Lack of muscle growth). Can someone please help me as i want to get the way i walk back to normal. I am under 18 years of age, older than 15 and i am male. I have no previous health problems and this condition has been going on for about a year now. I don't know if this has anything to do with this problem but my vision i see in dots sort of like pixels from the TV and no one can figure out why my vision is like this either. I am deeply concerned about this as the problem seems to be getting worse and no one has a clue what is wrong????