Thanks for the question. You should ask your doctor about your specific situation and any health issues that may arise from masturbation. Both your personal health condition and method(s) of masturbation may give your doctor some cause for concern that you or I would likely not otherwise recognize.   In regard to your question about the prostate becoming enlarged, you may find this article on masturbation and prostate health interesting. It is a bit dated, but helpful nonetheless. You may also appreciate this story about research that suggests that masturbation may cut the risk of prostate cancer.