Dry shampoo is the the best eg Klorane is very gentle and a aersol spray . Or Moo Goo have a dry shampoo too, but it is a talc like/cornflour dispenser so have to rustle it into the roots.
(Don't worry if you decide to stop cold capping, its not for everyone , nothing wrong with the chop and a synthetic wig -it does grow back quite fast once this chemo is all over ,and I have heard cold cap can be quite painful and make chemo day so much longer. Glad you have the choice. Be kind to yourself. You have a lot going on.)
re pain- 'motion is lotion for the joints ' as the cancer rehab and prehab EPs keep saying- go for a walk on the days you can if you aren't atm.Or some gentle stretches . Stress/anxiety also makes pain worse. If you don't already , now is the time to practise meditation and mindfulness. It's science, not woo woo. A friend made me do it when i had chemo, so glad she nagged me to keep trying.
https://www.cancercouncil.com.au/cancer-information/living-well/complementary-therapies/podcast-meditation-and-relaxation/