cindisue, you had several good suggestions for your leg pains. I just discontinued mirtazapine (SNRI) after starting it in 2001 (believe it or not). At that time it was a life saver for me. My anxiety was so severe as a result of PTSD.
I never had any side effects except for a major weight gain (not a good thing in the long run) but at the time I was unable to eat due to anxiety/panic. And could not sleep...obviously this medication was exactly what I needed. And I suppose I simply continued with it - as my severe panic disorder, to this day, remains with me.
However, after 22 years it was no longer effective and gradually came off of it to start a new SSRI.
I never had any leg issues...and I remember at the time discussing side effects with my psychiatrist who never brought up possible leg pains as a s/e and never did during my entire follow up with him.
But that's not to say mirtazapine is not the culprit with your leg pain.
I would simply say continue to monitor it but if no improvement perhaps further testing is needed to rule out multiple potential causes - & there are many. Good luck.