Hello, You are suffering from testicular pain. After an accident, you had one of the testicle operated 13 years back. Since you are having pain, reduce your daily activity, take a little rest. Do not unnecessarily strain. Cold compress at least twice daily may help. Take Naproxen or Combiflam, one stat when required to get relieve from pain and inflammation. Get clinically examined by a Urologist or GP to detect any infection, swelling, bruising, tenderness, torsion, etc., as it may be indicative of varicocele, testicular torsion, hydrocele, hernia, orchitis, etc. Get urinalysis (R/E and C/S) along with the required investigations done. You will be accordingly treated with medicines or recommended surgery if required. Not all people have symmetrical shape of the scrotal sac / testis. Do not get bothered about the shape. However, for cosmetic reasons if you want symmetry then you can talk to a surgeon or plastic surgeon regarding it. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician