I was a quite good runner when I learned in high school, I have some cups from that time. Anyway, I started working out (bodybuilding) 2 years ago, and now I'm kinda sick with that thing. As Arnie said, the pump is like cumming. Anyway, I can't be a good runner and a good bodybuilder in the same time, also bodybuilding do damage to my health.

What should I do?

Practice parkour(freerunning). You need to be quiet strong for this (workout alot) And you run almost constantly.

http://www.americanparkour.com/