Should I continue to take Norflex for chronic neck and shoulder blade pain if I have side effects such as muscle spasms, soreness and chest tightness?

First, you should know that these side effects are not usually seen with Norflex (orphenadrine). However, this medication can cause tremors, sometimes related to fatigue caused by the medication. Therefore, I would suggest that you stop taking it and talk to your pharmacist about this effect and the possibility of starting Duloxetine sooner. It is not impossible that all this is a coincidence, but I would not take any chances. Thank you for your inquiry.