Help…muscular issues, no help from gp

Hello,
I hope I am ok to post this, new member. Desperate for help with what I am suffering..will try and keep short.
I am suffering with extremely uncomfortable muscles, legs are wobbly to walk, can’t do much standing, strange chest sensations with feeling of breathlessness, my eyes often feel strange (like not working properly), weak strength of urine flow, on/off laboured swallowing, can’t always open jaw fully, and often can feel little lumps under my skin. Lots of other little things.
Sometime ago I was diagnosed with Chronic fatigue syndrome, something I always questioned as my problems do not behave in the way CFS sufferers say. Also many of my symptoms do not fit CFS at all. However, due to that diagnosis dr’s do not take anything I report seriously, no support, help or interest.
Recently I had a scan contrast. I have had in the past without issues but this time my muscles and breathlessness and mobility have been severely affected within hours after my scan. Go not interested, says allergy. Makes no sense as been ok before.
My father was recently diagnosed with polymyalgia/polymyitis (this alerted me somewhat as can be family genetic).
When I search my main symptoms it comes up with myasthenia gravis. I’ve no idea anymore, all I know is my life in a bit of a mess suffering all this and just left to it.
Can anyone tell me if my symptoms represent a muscular / neurological condition, how can I get the right medical specialist (and which type) to help, even take seriously?
Any help would be so appreciated as I’m at my wits end.
Many thanks in advance,
L