muscle spasm
"I find Flexeril 'tops' for killing muscle pain associated with spasm, knots and/or injury. Compared to Valium (which I also have) the Flexeril does a better job for the actual pain & spasm. However, Flexeril does have heavy side effects which could discourage first time users: 
- Dry mouth and eyes.
- A 'tight feeling' of the upper chest & bronchioles (very similar to what a high dose of Benadryl does).
- Slightly blurry vision.
- A substantial drowsiness which, for me, occurs about 4 hours after taking the dose. It becomes a struggle to stay awake. 

Definitely never go above the recommended dose - because of the harsh side effects."