This may help your tense, or sore muscles.

3 years ago, I pulled my neck so bad, that my muscles in my back went into a spasm. I was sore for quite a few weeks from this and I had to take it easy from work and I missed a session or two of Pilates. (I did some gentle stretches at home.)
When I did go back to Pilates, I had to take it easy with the moves given and I was in no predicament to do the same exercises as others were doing, as it would have aggravated the condition, so they were adapted.

When it was suggested I take a break, I was given a Spiky Ball. I had to stand with my back near a wall, then place this ball between my back and wall. I was to then bend my knees a little bit, then back to standing, so that this ball was rolling up and down my back. The Spiky Ball, you allow it to go on soft tissue either side of your spine. (Don’t use the ball directly on your spine itself.) It massages your back while you are doing this, helping your muscles to relieve tension and relax. I had never used one before, till then. But after using one in class and finding relief, I ended up buying one myself.
The one pictured below, I bought from Amazon.

blue spiky ball