Sore Stomach - Male

Last three days I have had a sore stomach.  Kind of feels like I done some sit ups.  I haven't exercised in years.  I first noticed it on my lower left hand side of my somach. (right above the waist line of my left side).  Now it seems like te entire stomach is a little sore and and sore when I push on it.   Is this serious and what should I do.

I have been eating a little but not much.  This may be a seperate issue that I have from time to time as well:  Sometimes when I eat, even if I don't eat too much I feel super fool as if I just pigged out.  Kinda feel bloated from time to time even when I don't over eat.  I do have asthma.

I also seem to have a hard knot right under my rib cage in the center.  It is hard and I have had this for a few years now.  Seems to get irrated when I over eat or am extremely stressed.

Any suggestions or help would be appreciated.  Thanks to any advice given