This is Dr. david
many of your symptoms are non specific and don't point to one diagnosis.
your lyme titers have been negative.
lyme usually causes fevers and rash
you could have excessive anxiety symptoms which can magnify other symptoms and also cause benign fasciculation twitching in your body and over sensitivity, increase emotional reactions, brain fog, muscle tension, stiff neck, headaches,
bell's palsy can be caused by viral infection which can cause body aches and pains. sweats and fatigue.
you can push for a new lyme titer, I bet it will again be negative
you can get a course of doxycycline, but it doesn't sound like you have a lyme disease at this point
have you ever taken anything for anxiety symptoms before?