Masturbation alone should not cause these things - altho some guys do it so quickly that they can't last long during intercourse - you've kind of trained yourself to *** quickly! Try masturbating with a start & stop technique, that may help you last longer when with a partner. Sexual activity of any kind will not affect hair loss. Masturbating too much COULD cause you to become de-sensitized, also, some guys get too accustomed to a particular pressure, speed, etc., to the point that being with someone doesn't give them the same type or level of stimulation they need. There's no correct frequency of masturbation, it can be different for everyone, but if it's too much for you, it could be a problem, so cutting back a little might help...
Side effects of masturbation can include focusing too much attention on the feeling in your penis (premature ejaculation) and too much on the physical action (erectile dysfunction). This also happens during intercourse. Without knowing how to balance your sexual focus you may continue to randomly experience these issues. Best to get them sorted before you meet someone you like.
I`m not a doctor but don`t think (from a long experience) any of the symptoms are caused by masturbation. Premature Ejac. might decrease w/over masturbation but not a cause of it.You can throw out hair loss 1st.