For A Couple Of Years I Feel As If My

For a couple of years I feel as if my diaphragm has gotten larger. It feels like a hard lump. I am 40 yrs old now and a little over weight. As far back as I can remember, when I was really skinny, I do not recall this. When I lay flat on my back and look down at my feet, I see a big hump (diaphragm)..
Is this normal? I am a 40 year old man. Now when I lean on it or bump it, it kind of hurts.