I'm recovering from dengue and chikungunya. My neck is very stiff also my shoulders, my back is tense. Swallowing is difficult. I'm having muscle/joint weakness and pain. It's hard to exercise.
My question is: What exercises should I start with?
Before you do anything, you should ask your doctor if there's anything you should avoid doing or anything you should specifically do. I'm not sure if there's anyone here with the training to speak to this specific circumstance.
As a general rule, it's usually not a bad idea to start with walking, stretching, and manipulating extremely light weights. The most reliable indicator that something is wrong is pain, so you want to feel loose and challenged, not hurt. When something starts feeling too easy replace it with something slightly more challenging, and go from there.
Good luck on your further recovery!