Ive Been Getting Fat(big Bloated Belly, Looks Like Im Pregnent),

Ive been getting fat(big bloated belly, looks like im pregnent), and Ive always been in good shape. If I eat a few bites of food I feel bloated, but I still eat my fair share, usually healthy(ier) stuff. Ive recently had full physical and EKG, seems normal I guess, yet my chest - heart area seems to feel sore and Im more tired than I should be (I think). I've always been a pretty active guy, now Im almost 40 and slowing down it seems.. Mainly my stomach looks like a bowling ball and I cant pinch an inch, its solid! What should I do?