Doc prescribed this for my pissing problem due to enlarged prostate after Flomax sucked so bad. Same side effects as you. Felt like someone beat my legs with a bat. Went natural for the enlarged prostate with saw palmetto pills. They actually work for that.When I was visiting my buddy in Chicago his wife who works at a doctors office gets free samples packs of all the stuff. Gave me a 4 pack of real Cialis. It works great but I had horrible lower back pain and leg cramps for 3-4 days. So bad that I could not sleep. At first I did not relate it to the Cialis but the next time I took the same thing happened. Thought maybe it was just me so a third time the same thing happened. Went online and this is a side effect for many.