Having dull aches/mild discomfort between my lower abdomen and scrotum when i masturbate. both my testicles are also horizontal. any concern?

Prostatitis?: Aching in the pelvic region with male ejaculation might be associated with a prostate infection and a doctor can discern. Horizontal station of the two testes is a normal variant.

Orgasm in men: Can come with symptoms as you describe. If your testes are truly horizontal, a local doctor can confirm this for you. If the plumbing is still working correctly, I do not know of anyone that would surgically do something to make them 'upright'. If symptoms progress, you should see your doctor.

Check it out: Npmay want to see your doc to make sure no infections present.