I have lower stomach pains... any ideas???

Now, I just started a 3rd job where I am really busting my hump, using a lot of muscles I never knew I had! Plus My wife and I recently split for good, plus I do not have the best diet either.... My pains are localized to the middle lower part of the stomach. Feels like soft burning. It is not a sharp pain, and I know the appendix is on the right side... Your best guess??? Stress? Work? Diet? All of the above? Any help?