If the cord is around the neck of the baby, will I have any pain or will I get to know only when I do an ultrasound?

It is very common for the baby's cord to be around baby's neck. It is only extremely rarely that this causes a problem. You would have no symptoms of this, but an ultrasound scan could show that the cord is around the neck-though even if it is, nothing would or should be done. Babies are very frequently born perfectly healthily with cord around their neck.