Hullo gemma,
it is very bothersome but it can be treated and kept under control.
I hope you have a good dentist. A bite raiser or mouth guard is very helpful, to be worn at night.
Try and avoid stress, not easy I know.
If it becomes painful (i assume at the moment the ache or pain comes and goes), don't delay, see your doctor or an oral surgeon quickly. Muscle relaxants will stop the jaw going into spasm. Physiotherapy exercises are often helpful as is holding something very warm, eg a hottie, against the affected side.
If it does go into spasm, a combination of muscle relaxants and anti-inflammatories are usually prescribed.
Don't think beyond that atm. Many people have the condition, well controlled, and are only bothered on occasion. Yours may not get worse and might even improve.
It is quite usual to have tongue, cheek and lip pain, also referred pain on the same side of the head as the jaw problem, around the temple, and neck.
I hope your tmj dysfunction is not too severe, my dear. Take care of yourself.