AnnieBrooke is right - I do recommend yoga. You can check out
YouTube for videos that you can follow along with to learn how to do it.
Here's also a link to an article indicating a variety of exercises you can do, using only your body weight: https://www.mayoclinic.org/healthy-lifestyle/fitness/expert-answers/body-weight-training/faq-20147966
You can also try some light weights. If you don't have any actual weights use a couple of 16 oz cans of vegetables or bottles of water.