Shoulder pain during serve

Can someone please dissect my serve. Thank you very much.

1. I keep getting shoulder pain whenever i try to serve. I’m thinking its the rhythm, this is happening when i try to put some speed into it. Or is it the incomplete looping motion.

2. My grip is changing during the serve and unable to serve from my duece court.

3. I am trying pin point stance and started to take the jump. A bit confused on body coiling and uncoiling during the serve. Do i need to face away from the court until the contact?

4. Toss is also sometimes all over the place. Either too high breaking my serve motion.