Sorry I am vastly behind in responding to comments. For those who were following the Muscle Spasm Saga with interest, I just want to let you know that my back is feeling fine. It took about two weeks of rest, Flexeril and Ibuprofen to get there.
Last Thursday, I had a PT assessment. The gist of what she said was that I have some really big strong muscles, such as my quadriceps and some weak muscles like my hip flexors and trapezius. When I do the core exercises that are meant to work the smaller, weaker muscles, I tend to cheat (either intentionally or not) and the big muscles come in to do the work. Somehow this pulls everything out of alignment, triggering the spasms.
The Physical Therapist gave me some exercises and tubing and wants me to come in twice a week to work on the weak muscles. I don't think this is going to happen, but I am going to try and stick to cardio for awhile, and maybe go back to the push-ups, which were not giving me muscle spasms.
The sore throat turned out to be a big nothing-burger. No infection. Basically I spent the time and money to go to the doctor so she could tell me to gargle with salt water, drink hot tea with honey and maybe not talk so much.