Im getting mild numbness in my penis when im sitting.i still have sensitivity but its like mild pins & needles. iv a history of l5s1 impingment & sacroilliac pain and front pelvic pain.iv no idea what could cause this or if its worth getting checked?

The same kind of nerve impingement causing your sacroiliac and pelvic pain probably now involves nerves serving the genital area. Even if these symptoms themselves are not very bothersome, they suggest you may be at risk for erectile dysfunction. Discuss soon with the doctor managing your lower spine condition. Good luck.

This sounds neurological secondary to your impingement. Suggest get checked by a neurologist or Urologist. When primary cause is treated the penile sensation should get better