Good old side stitches - makes you feel like your liver is falling out - or at least torn loose. They have derailed my attempts at running many times. I found that they happen to me more often if I don't warm up properly first, and are more likely to happen if the weather is too cool. One thing that helps me get through them is to take a
deep breath, hold it, and press my hand firmly right into the painful area. Pretty soon the pain is relieved enough to continue. I believe that lack of conditioning contributes to having that kind of pain too. This time, before I started cutting and started trying to run again, I worked my way up to eight mile fast walks first. Now when I run, I can make it a couple of miles (not all at once though), run hard for 1/2 mile, walk 1/4, run hard 1/2.... until I just can't run anymore. Then I finish up by walking the rest of my eight miles. Works for me, might not for you.