I get acute pain when i walk short distance 200' or so in the center of chest ribs are very tender to touch and pain radiates to arm pit on left side no swelling or redness. it's been daily for 5-6 weeks howver it started about 4years ago ,but only once in several months and not so severe. stress test come out ok although symptoms occured while on the tradmill,but dr said ekg was fine WHAT'S GOING ON?