Request for Simple Stretching and Strength Building Exercise Suggestions

As my Lyme treatment progresses I am slowly regaining a tolerance and ability for exercise and physical activity. Because of the exercise intolerance caused by Lyme and the treatment side effects I have lost a great deal of upper body strength and flexibility. I would like to very slowly start incorporating stretching and strength training exercises into my week. I know many of my friends here have had similar issues and may have some ideas or resources. I would like to maybe integrate some very basic yoga exercises into my weekly routine. But right now I need things to be very bite sized and simple.

If you know of some good bit sized videos or exercise explanations particularly aimed at those recovering from long term illness, please feel free to share in the comments.