I recently got three different ed medications from my doctor, sildenafil, vardenafil and tadalafil. the only one I have taken was the tadalafil 100mg. did not work but the following night severe lower back pain slept about an hour that night. no matter what I did lay down, walk, standing or sitting bad pain no sleep. when at work didn't have bad pain still felt it though, at night when I layed down with in minutes pain so bad I wanted to go to the hospital. this happened four nights straight, 6hours sleep total. should I be worried about the other two, both of those are 100mgs also. thank you