Vitamin B-Complex & Teeth Clenching

I recently started taking a vitamin B-Complex(50)(split in half, taken
half in morning and half in evening) for chronic pain, especially lower
back and sciatica pain. I was amazed at how much it seemed to help the
pain...more than any of the over-the-counter pain meds have helped. It
also gave me some much needed energy and mental clarity that I have
been lacking due to my back and neck pain. The only problem is that I
can feel a lot of tightness now in my jaw and many of my muscles feel
like they are tightening up. I have suffered TMJ for a while. I go
frequently to a chiropractor. When he adjusts my neck it helps my bite
and the TMJ. But now it definitely seems that the B-complex is
exacerbating the TMJ...not to mention tightening up other muscles(which
won't help my back and neck pain). I would hate to stop taking the
b-complex and lose the benefit it has given me with the nerve pain, but
I don't think I can continue if it is going to tighten up my jaw so
much. My question is, could this be a certain b vitamin in the
complex...Could I get the energy and pain relief by taking one or two
of the b vitamins separately. I know you are supposed to take b's with
other b's for balance. But I don't think 25-50mg would throw off the
balance too much. Any suggestions/help is much appreciated. P.s. I
don't think it's from getting too much energy from the B's. I don't
feel too much of a wired feeling...and have no problem sleeping at
night...it feels mostly like the muscles(especially in the jaw) are
tightening up.