The sensation in the stomach could be a lot of things, from mild acid reflux, to occasional indigestion; however, if the pain is moderate to severe (including a very bad burning followed with constipation), it could be something much more serious.
To give you an understanding, I will give you my history.
For the last 3-6 months I was having these terrible stomach aches, a really bad burning sensation in the pit of my stomach, these would happen maybe once a month, but it was just the beginning of more problems to come.
They were followed by a uti, which was very, very uncomfortable, and then, the other night, I had a sereve pain in my testicle, like I had pulled it, or hit it. Probably worse than being hit there.
Anyway, I went to the docs today, and he diagnosed me with a hernia. However, making me cough and feeling my stomach did not reavel it. There are other areas they can feel to find out if it's a lower groin hernia, which is where the testicle pain fills into your equation.
Your best bet would be to see your primary care physican or a urologiest. Explain to them the problems, and have them check for it, very throughly. If it is like mine, it can be caught early enough and no damage, just discomfort can come out of it.
Having surgory done this week to correct it.