Back pain - yes I got that with Ciallis
Lack of concentration and not sleeping - Now you mention it yes but I put that down to the "stiffie" I now had!!
Ciallis definitely worked for me but I could not stand the side effects. I thought Viagra was better because at least the effects (all of them! ) wear off and don't last for days like Ciallis.
Best of all are the caverject injections get the dose right and its just like old times!
Fortunately after what is now 3 years I can make do with a Durex cock ring most of the time, even had a nocturnal erecting the other night - that was a first for non drug assisted!!