Well you've got a lot of things going on there at one time, all of which can be normal behavior, or can also be a problem. If he's shedding he could be stretching his beard out to looses his skin, but the "twitching" is troubling. What do you mean by "twitching"? He could also be opening his mouth and gaping because he's too hot, or he could have a respiratory issue. We need more information about him and his setup to know. Can you post some photos of him, his enclosure, and his lighting? How old is he? How long is he from end to end, and do you know what he weighs?
How large is his enclosure? What brand/model/type (compact, coil, tube, or mercury vapor bulb) of
UVB light does he have? How old is it? Is it mounted inside his tank or on top of a mesh or glass lid? How far away from his main basking spot is the
UVB light?
What brand/wattage/type (compact or coil) of basking bulb does he have? Is it right alongside the
UVB light? What are the temps of his Basking Spot, his Hot Side Ambient, and his Cool Side Ambient? And what type of thermometer are you using to measure the temperatures (stick-on, digital probe, or a gun)? How many hours per day are his lights (UVB and basking) on?
What is his daily diet (what type of insects and how many per day)? What type of greens and veggies is he offered day? Do you use a Calcium and/or Multivitamin powder? If so, what kind and how often for each? Is he pooping regularly?
I'm asking these questions because any kind of "twitching" is very often a sign of either a calcium deficiency (MBD) or a vitamin B1 deficiency, which is typically due to inadequate UVB and UVA lighting, improper diet, improper supplements, or all. And the mouth gaping can a sign of an improper temperature gradient inside his enclosure. All of his symptoms or behaviors can be caused by inadequate or even dangerous bulbs, like most coil lightbulbs, colored lightbulbs, etc.