People need to be able to distinguish the difference muscle soreness from breaking down the muscle fibers, which will cause it to grow, once feed and rested. This will usually happen then day after and can last a few days. lactic acid build up, the burning sensation when doing high reps, this is immediate. joint/tendon pain. can be immediate or a few days later. Lasts a long time muscle tears, usually immediate, lasts about a half a month or more depending on severity i try to accomplish muscle breakdown soreness, as it is a good indicator that I worked out my muscles. others I try to avoid.