Another possible cause of your extreme morning stiffness could be rheumatoid arthritis...before I got on the proper medication, I had symptoms very similar to what you're describing, and RA is always worst in the mornings.
I agree with other posters that what you are experiencing is definitely not sleep paralysis, and you need to talk to your doctor and describe your symptoms in detail. Best of luck to you!
Life is not about
waiting for the storm to pass; it's about
learning to dance in the rain.
Possible Fibromyalgia, Rheumatoid Arthritis, Type 1 Diabetes, Grave's Disease