Hi Thank you for asking HCM. I have gone through your query. Your problem of itching can be due to fungal infection or dryness. You should also avoid using soaps and irritants to wash the genital area and instead you can use saline or warm water. If you were my patient with such condition then I would recommend using ointments with combination of antifungal agents like miconazole and corticosteroid like flucinolone for local application. Back pain after masterbation is most likely due to wrong postures you assume during the act. Hope this may help you. Let me know if anything not clear. Thanks.