I have chest tightness 5 min after exercising but usually 15 min after it disappears. a friend says its endorphins and i should go to a dr.?..

My suggestion is to: See your pcp or an internist as at your age and with your hx of high bp, one needs to exclude a heart problem. It'll be safer for you to do that, as you might need to turn down your exercise-intensity or frequency a notch or two, to curtail this chest tightness. So seeing them would be fruitful for you as then with everything being normal, you could continue exercising for ever. So do see the pcp.