What Causes Legs, Arms And Neck Pain With Dizziness?

This has been going on for a few days. And I saw a doctor who said to follow up next week to address that I still have concerns.
-My body hurts! Not like I'm sore from exercise, but like I've been badly, badly beaten up.
- My left arm keeps going numb with the exception of a pain in my shoulder and wrist and a weird shooting sensation in my inner elbow sometimes.
- My legs are just giving out on me suddenly. I don't fall, but I nearly do and it's disconcerting as heck.
- My left thigh is cramping up badly... and it feels like the backs of my knees are made of rotten rubber.
- My feet, again, especially on my left side, feels badly sprained (I've sprained that ankle badly before)
- A splotchy rash has appeared on my thigh and on my shoulder- there are other little bumps and they itch and burn like the dickens.
- I'm a little bit dizzy/ my eyes are playing tricks on me
- my neck really aches so as it hurts to turn and hold my head. My jaw especially.
- The bottom of my ribcage keeps feeling like it's getting compressed.
- My bloodwork showed an elevated MPV and chloride serum towards the high end and platelets at the low.
This is really awful.