I'm 21, male. Is there any relation between stress, masturbation and hair loss? (Photo)

No, masturbation does not cause hair loss. This needs an in-person evaluation. I suggest seeing a hair loss expert now to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like prp/progesterone and/or hair transplantation. See an expert. Best, Dr. Emer

Thank you for your question. Yes, stress causes hair loss. I suggest that you move forward and consult with a board certified facial plastic surgeon to determine your candidacy for NeoGraft Hair Restoration because the procedure can create a natural looking result with no incisions and a short recovery period.
Best wishes,

Anxiety,stress and masturbation do not cause  hair loss.Receding hairline is not a hair loss because of ongoing process of androgenetic alopecia but  a simple juvenile type maturing of frontal hair line.  That is seen almost every young boys almost between 16-21 that have a very rounded hairline without recession in the corners.  Recession in the corners is a sign of mature pattern male frontal hair line.