I take flexeril (cyclobenzaprine hcl) for muscle pain from charcot marie tooth disease. Lately it has been feeling like its hard to pee. Could this be from the flexeril (cyclobenzaprine hcl)?

CMT is a neurolgical. Disorder that has many many different types. Some of which can affect the neurolgy of urination, bladder control and post void retention of urine. Other things can also simulate CMT ( such as syringomyelia) but in fact be not a hereditary disorder but need treatment. So talk to your pcp or neurologist about this.
Possibly. Flexiril is a strong skeletal muscle relaxant... It can slow down the entire GI system, causing constipation, and occasionally painful urination... I recommend drinking lots of water when on the medication... Confirm with your physician to rule out other potential sources of the discomfort...
Possibly. The best thing would be to stop the Flexeril (cyclobenzaprine hcl) and see if the problem resolves. If it does not then you should discuss the situation with your doctor or neurologist.