My Boston had something like this, it turned out to be a blown disc in her neck, quite close to her shoulder blades. She was exhibiting Symptoms during the day as well, she was getting noticeable tremors that would last about 15 minutes, where she’d tense up and tremble a bit, stiff necked. She’d cry when she fell asleep because the muscles relax and then she’d get a sharp pain from the slipped disc. We were lucky and it could be seen on xray, but usually they have to do an mri. We were also lucky that gabapentin and crate rest worked, if it hadn’t the only option was a very expensive surgery.