I have a lump under the foreskin of my penis that is moveable and not attached to the actual penis. i haven't been sexually active as of late. should i be concerned?

Cyst: What you described suggests a cyst, a sebaceous cyst. It is not dangerous, but you should get it removed at your convenience. Have a healthy diet, exercise 30 minutes/day, drink plenty of water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/. Get HPV vaccine. Wish you good health!