Bicep Pain

Question
18 months ago I ruptured my long head bicep. Before the tear I bowled about 20-30 games a week. I抦 still a 225 to 230 house pattern bowler (haven抰 bowled on a house pattern in three years) and about 205 to 210 sports league bowler. I抳e bowled for several years in the PBA regional抯 in my early 20s, so my knowledge in the game is above average.  I抦 still a student in the game, always analyzing the technologies and concepts around drillings and oil conditions.  
I was cleared to 6 months after the surgery to start bowling 1-2 games a day again or until my arm told me to stop. I did this for nearly 3 more months at 40% to 60% effort. At about 11 months I was able to bowling 100% without fear. I only throw a 14 pound ball do to the surgery. For the next 5 months, I bowled pain free and was tearing up league and tournaments. Then the same pain that I felt before the tear was coming back slowly.  I could bowl 8 to 10 before I felt any soreness.
Let me describe my game real quick. I consider myself a stroker, but everyone calls me a lair because I can generate about 400 rpm on the ball. I don抰 have a lot of extra arm movement.  I have been working on freeing my swing up for years, and it seems like the more I free my swing up the sh@t I put on the ball. Now I have a very strong hand position. My starting hand position is palm up, wrist cocked to the left and about 20% cup (I抦 right handed).  I抦 able to hold this position through the full swing, so at release my fingers are located in the strong quad (7 to 8 o抍lock)  and I just roll the wrist and fingers up & out the back of the ball (I track about 1?緮 from fingers and 1?2?from thumb depending on the ball).
So back to the problem, the pain started happening with fewer and fewer games bowled. To the point that I could even complete 3 games in league without it feeling like someone was stabbing my bicep. I went to get my arm looked at because naturally I was starting to become concerned. They did an MRI and everything was just fine.
Forgot a fact, I抦 in the active duty military, so I crossfit a lot and stay fit. Now, this pain that I抦 talk about never occurs during any of my fitness workouts (pull-up, push-up, weight training, you name it, my bicep never effect any of my military training), but as soon as I put a bowling ball in my hand and bowl a few game I抦 in pain like I抦 about to tear my bicep again.  
Any thoughts? The doctors are clueless, and I抦 not ready to walk away from the sport.  Why just bowling?

Answer
Vingator,
I can only suspect that your current set-up, with a stressful cupped and cocked wrist position, puts too much strain on your hand, wrist and arm. How long since you've had any kind of fit change? I'd suggest a ball fit check, as the fit might contribute to the need for grip pressure. And I'd suggest you work with a coach to get you into your favorite wrist position at the height of the swing rather than thru the entire swing path. The tense swing is extremely difficult to control, when you observe many top players their swings are very relaxed and free.

Best example I can think of is Chris Barnes. At set-up he's very cocked and rigid, hand wrist and arm. But, the second he starts his swing the wrist relaxes to almost straight, a free swing follows with the starting position revisited at the top of the swing, where he loads up to deliver his strong, low axis rotation delivery.

Thanks for the question.