TENDENITIS ON ACHILLES TENDEN

I HAVE HAD TENDENITIS IN MY ACHELLIS TENDEN SINCE OCTOBER OF LAST YEAR.
I LIKE TO PLAY BASKETBALL AND SOFTBALL.
THE TENDENITES KEEPS ME FROM RUNNING FULL SPEED.
THE PAIN IN MY HEEL BECOMES VERY SHARP AND LASTS FOR DAYS WHEN I RUN AT FULL SPEED.
IF I DO NOT RUN AT FULL SPEED I FEEL A SLIGHT PAIN WHILE I PLAY THE GAME AND THEN NO PAIN LATER.
I STOPPED PLAYING SPORT FOR ABOUT FOUR WEEK AND THAT HELPED BUT AS SOON AS I HIT FULL SPEED THE PAIN RETURNED.
WHAT CAN I DO TO CURE THIS PROBELM AND IS THERE ANY USE IN ORDERING THE SPECIALIZED WRAPS OR OILS THAT ARE ADVERTISED FOR THE CURE OF TENENDITIS