Pain in left side of stomach. Is this?

Around six months ago I had pain and swelling on left side of my stomach. I consulted a doctor he had done sonography but everything was normal. He suggested to have light diet & After two days of that swelling and pain in morning I went to toilet after completing the natures call in 5-10 min the swelling started reducing and I felt that reduction and it came back to normal. Again since this morning I am having that pain and bit swelling on same area(Left side of my stomach). While bending to touch ground am feeling that my body should not bend from left side. Am not feeling comfortable with this. Can someone guide me what exactly is this? I prefer eating non Veg twice a week. 3-4 Cigg a day Alcohol once a week I would like to explain the area:- from Navel to extreme left.