I had hair transplant 22 days ago. What shampoo should I use after surgery. Also should I use Rogaine or not?

At 22 days you should be safe to use whatever shampoo you like, no risk of damaging the grafts. That being said any baby shampoo is gentle enough that it should be fine for using on your new hair,  even well before 22 days. Nothing wrong with using Rogaine either, just try to get your doctor's approval first. Many people start using it 2-3 days after their surgery.

We recommend a simple Head and Shoulders or other anti-dandruff shampoo with zinc to keep your scalp healthy, clean and decrease itching post transplant. This is also good for maintenance washing. Another ingredient is ketoconazole that is found in anti-dandruff shampoos and those for hair thinning because it is considered a mild DHT blocker. Even if you don't have dandruff, these ingredients can minimize the low level of inflammation that may be present in the scalp in male pattern baldness. Rogaine/minoxidil can safely be resumed after transplant within about 10 days. If you are interested in helping your native hair, it is important to maintain your medical regimen for hair loss with that that and/or finasteride even after you have a transplant.