All motors are not in sync after flashing pixhawk and using it with raspberry pi

I have install pixhawk and tried to takeoff with raspberry pi 3 but all motors are not rotating . Kindly help me , my project submission date is near… I have same setup as yours plzzz help me out. Is it related to wrong configuration or any parameter?? plzz explain me step by step what to do with this setup

This could be due to many factors, wiring, esc calibration, radio, etc …
Your best bet is to exactly follow the wiki and guidance, starting here:

I am using simonK esc, they dont need calibration?

They do. In fact as far as I know all ESCs (flashed with simonk, blheli, hobbywing proprietary, etc …) do, except for DJI escs.

Now they are spinning at same time but at different speed, what to do now??

This could be perfectly normal if you quad is not level, or imu is not calibrated. Even if quad is level or accel is calibrated, a slight difference is not unusual.

That said I’d redo/verify esc calibration just to be sure. Also calibrate imu and radio, check wiki.