Sounds like TMJ - a collection of disorders of the temporal-mandibular joint. It may have nothing to do with the gh...it may to do with sleeping habits, stress, teeth grinding,etc. or it may have hormonal influence. Check the following link for a primer on TMJ.
I thought that might be it from grinding on my teeth when lifiting heavy sometimes and also I bite my nails alot and do grind my teeth! I have been trying not to do that and it has gotten better lately even with continued GH use! So I don't think it is the GH!
I have been on GH for about 6 months and I started to get this same problem about 2 months ago and it went away after about a month. I don't know why but it actually got better after I increased my dosage. - cbeaks