Hi, I do a fair amount of running , at least twice per week at a race pace between 7-9 km's. I've only missed 4 runs this year when I pulled my back before Easter, so I'm not a novice or by any means unfit. My weight is perfect for my height and age. Recently I've been experiencing side sticthes on the right side every time I run, normally starting at around 5 km mark or when I attempt to up the pace. The only way to stop the pain is to simply stop running, continuing exacerbates it. I always run in the early / late morning so I don't have a lot of food digesting in the stomach. It happened during a recent race, I kept going but almost fainted at the finish line :-( I thought it might be appendix related but the doctor dismissed this theory and thought it was more likely to be a muscle strain. Anyone have any experiences or advice on this ?