Complicated question. If you only have a month you better get moving. The worst thing you can do now is to go too hard thinking it will get you in shape faster. It wont.
Start out slow at a medium pace.
The stomach cramp could be runners stitch. Sometimes caused by dehydration, sometimes from running form, and sometimes from going too hard. Could be a combination of all three.
Try to isolate the problem by tweaking each one at a time.
For a small piece of the form puzzle, pay attention to which foot you exhale on. If you are always doing it on the same foot, change it up a bit. Sometimes people us their dominant leg to push off from which causes torsion on your torso. Try and use each leg the same....try to be symmetric.
Many times the side stitch is caused by breathing technique. Make sure your chest is RELAXED and your shoulders are down and free of tension. Don't flex your stomach muscles like you are at the beach while running. You should 'let it all hang out' because you get much more oxygen that way and you are more relaxed.
Most of the time the cramp has to do with a few of these coupled together. Almost Always comes from going at too high of intensity plus something else. Everybody feels great the first part of the run. We all want to hall A$$ down the trail, but the good runners finish as strong as they start. That should be your goal. For the rest, I could go on forever.
Excellent book on running from a master.
