Side Strengthening for Fast Bowling

Hi all, wondering if anyone has expertise treating Side injuries in fast bowlers (cricket) I have suffered a tear in the muscle just under the bottom rib (oblique? intercostal?)the last two seasons when bowling. It is painful and hurts to cough sneeze and is tender to touch, this gets better in a week or so but due to the repetitive and strenous nature of fast bowling it has taken 6-10 weeks to resume bowling both times. I am preparing for this season and dont know whether simple side stretches or some sort of strengthening exercise (ie sit ups with a twist) will help prevent me sustaining this injury again. Obviously warming up etc will play a part as well. Any advice or link to exercises etc would be greatly appreciated
Sam