Burning sensation inurine. Burns alot.

It was started when i was doing gym, i was nt using spotter(langot),i started high weight,then i got a problem sperm ejaculation in my urine. i took advice of a doctor and took medicine till one month then i became all right bt still i was facing burning sensation during my toilet.i am facing it from last six months someone told me start drinking more water.i tried it. it did work fr sometime bt now i am again facing it.the present situation is that i feel burning sensation in urine and when i run or i do gym my penis muscle gets tight and smaller during physical activities, and when i end with physical exercise and when i go for toilet i feel more burning sensation,and if i dont drink water for 1/2 hour it feels burning sensation automatically in my urine tube part and around it.whenever i drink water suddenly after 15-20 minutes i feel i should go for toilet if i dont go it burns alot.main problem is that i m feeling burning sensation in urine and not able to continue with exercise