Stomach bloating after eating??

After I eat (anything) my stomach bloats right up like a balloon and its very painful. I have trouble wearing anything but sweatpants because its so bad. I have been having constipation and stomach pains so I have lost weight, but the bloating still is there. Been to doctors and had allergie tests, stayed away from certain foods, but still same pain and bloating. Anyone know of anything that helps that, any suggestions or anything that you know that works! ANYTHING! just for some relieft ...thanks