You may have an injury. Whatever it is, don't ignore it. A small twinge now could turn into a major injury later, leaving you temporarily sidelined. Fortunately, most injuries that result from physical activities are preventable. These cause pain that comes and goes, often has no specific onset, and may get worse over time.
Examples are tennis elbow and golfer's elbow.
Preventing injuries Start slowly. Increase the intensity and duration of your physical activity gradually. Always wear appropriate protective equipment. A helmet can reduce the risk of head injuries. Wrist and knee pads help protect your bones.