Hello I share your concern This pain might be caused by cialisis (tadalafil) or injury due to lack of lubrication Cialisis increases blood flow to penis and makes it hard, some time it may cause pain in penis due to vasodilation of veins in penis shaft and corporas. In my opinion you should use lubricants during sex to avoid injury caused by friction You can take ibuprofen for pain in penis if it is unbearable or reduce the dose of cialisis. Hope this answers your question and you will find my response informative and helpful. Please feel free to ask for more queries. wishing you good health Regards