I find Magnesium Malate so helpful for pain throughout the day.

See if ibuprofen helps your shoulder pain, that could be just from over use. Twitching and vibrations, burning feeling could be fibromyalgia.
Burning tongue could be just hot food or liquid, hormonal or burning mouth syndrome. Depending on what you see. Is it red, shiny, white?
I had all of your symptoms. Shoulder was from over use, tongue was burning mouth syndrome for about a year (tried everything from vitamins to mouthwash) nothing helped. Then it got better one day. Tremors and twitches head to toe on daily basis nearly 10 years, different places, frequency and length of time different. Usually not longer than an hour maybe few times a day. Floor feels also vibrating sometimes.

💜I get internal tremors every evening, like an electrical current, usually in my feet, but sometimes throughout my body, drives me nuts at times.....💜

Get your B12 levels checked, Low B12 can cause a sore tongue.
Magnesium Malate for your twitching muscles. Play around with your daily dosage, your dose is too high if your stool becomes loose. I personally take just under 600 mg throughout the day.
For your shoulder blade tightness and pain, using a massage ball and the wall or floor, break up the tightness and knots daily.
https://www.youtube.com/watch?v=DzSU2FiFKTM.
https://www.drbodygadget.com/self-massage/.

I get horrible muscle twitches and vibrations.