Can masturbating too much cause pre ejaculation?

No. Some sex therapists in fact suggest masturbating before a sexual encounter as possible technique to avoid premature ejaculation during intercourse.
Doubtful. Masturbating should theoretically make it more difficulty to achieve the next orgasm or at least reqire more time. Premature ejaculation is usually a heightened sense of stimulation with no control to stop an orgasm in a very short period of time. I do not believe you would have pe due to excessive masturbation. May need to discuss with a sex therapist.