Are these muscle spasms or something else??

My 4 yr old frenchie was a bit off yesterday and I knew something was up… she was still eating, drinking and going to the washroom but I just knew…. very droopy and not herself. This morning found her laying in a spot she never has, shaking a bit and her one side of her face was all wet from panting…. I picked her up but she is kind of stiff and you can tell she is uncomfortable and when I tried to reposition her she yelped a little. The vet thinks that it could be a muscle strain or pull of her chest or shoulder. She is sensitive in that area. No fever, everything else checked out ok. The thought of meningitis came up but that would require a fever so that is a back burner thought. She is giving her muscle relaxants and anti inflammatory meds and
We will see how she does with that. I just took her out she peed but now she has diahrea and there was a bit of blood coming from her bum so I called the vet and she said it could just be irritated from taking temp and checking anal glands but to keep an eye on it. She ate some yogurt earlier so I could give her her anti inflammatory and then she ate some chicken, rice and pumpkin for supper and took her muscle relaxant. She had a good sleep with us and i got her to take some cheese so I could give her the muscle relaxant again. She started shaking again this morning but I’ve noticed all the shaking, twitching is in her neck top of her chest area. I just spoke with my vet and she wants Annie to be on the medication for 2-3 days and then we will see how she is. If she is not better, then we will look into this more evasively but she is confident that since Annie had seemed to calm down and relax once the drugs kick in and she has only had w doses of the anti inflammatory and 2 of the muscle relaxant, that we are aimed in the right direction. It’s just every time she moves, she starts shaking again…Is that normal? Do I need to let the medicine work its magic after a longer period of time in her system?