In the UK? glandular fever

don't give up trying to find answers and to advocate for yourself.
also, consider bringing a friend or family member with you to appts. they can validate in front of the dr what is happening.

it sounds like you might be experiencing muscle spasms. there are meds that can help with that. but, finding a cause is also important.

MS can be hard to dx (diagnose). it can be done by PE (physical exam, neuro exam), exclusion of other diseases and MRI. i was dx'd by PE and MRI alone.
later i also had an LP (spinal tap).

there's something called the McDonald Criteria that drs go by to aid in the dx of MS. try looking that up. sorry, i don't know how to do links.