You should get the vet to check it out just in case, but if it is a cyst it shouldn't hurt your cat, you have the choice to get it removed, but wether or not you do it won't hurt it.
when soreness occurs, it is because of a build-up of lactic acids.
Soreness.
Injury caused by a blunt object does not usually cause immediate soreness or pain.
soreness
Yes
Ice
stretching, or relaxing
Soreness is caused by a buildup of certain acids in the muscles. Drink a lot of water, and move around. This will help to flush the acid from your system.
Make sure to stretch before and after exercise, it reduces the lactic acid in the muscles reducing soreness. If it's soreness from the rebuilding of muscle then it's fine but if it's soreness due to injury then don't exercise without consent of a doctor.
The main concern if you have soreness and pain in the epididymis is that it could be related to an enlarged prostate. This pain could also be caused by an infection in your system.
alot
Exercise and working out