How can I learn PHP and Backend development?

If you want to learn then search some free websites, who provides you free certification and give you more knowledge about it. Internet have many resources where from do you your thinks in free of cost.

for php, i dont think u need to go to any coaching. u can start learning it by your own. jst get one good book nd start learning. also there are many online tutorials. with php u also need to learn mysql. once u get enough knowledge u can start developing some demo web app of ur own as u r good in