Can you take flexeril 5mg bid and norco 10/325 together at the same time for knee pain injury and spasms it hurting bad.

Yes: Muscle relaxants and hydrocodone/acetaminophen combinations (and others opioids as well) are very commonly given together. They are both CNS depressants, and the effects can be synergistic or additive, meaning that 1+1 may equal 2 or 6. Don't drive or operate dangerous machinery or do anything requiring full motor skills after taking either drug (or both) until you know how they effect you.