I started taking myrbetriq 25 mg last Monday. Wednesday afternoon I found that I could not get up from a chair without severe discomfort. Having driven on Tuesday for 3 hours, walking around a flea market for 5 hours, and driving back home for another 3 hours, I figured I stressed my right leg and started taking Motrin 600 every four hours. I did not feel any relief. On Saturday I switched to Aleve and felt some relief. Today I noticed that I feel better late at night even before I take my second Aleve. I then thought my new med and read that a side effect of myrbetriq could be flank pain. What do you think?