cant pull lawnmower string, but the blade still spins, I hit something metal and it squealed?

You might of sheared the key on the crankshaft so now it screeches as it turns inside the blade mount. Shouldn't be hard to pull it off and take a look. I haven't fooled with one for decades so you better look up the make/model on-line to see if the mfg. has a downloadable owners manual for servicing.

Flip it on it's side and see if the blade is still attached to the shaft so the shaft is turning with the blade. If it isn't then repair the problem. THEN if you can't turn the blade with the brake off, the shaft is probably bent and the mower is toast. But if you can get it to turn freely and the shaft is good, you will have to remove the flywheel and replace the Woodruff key that holds the flywheel in time with the crankshaft to ever get it to start.

The first thing to do is to disconnect the spark plug. Any time that you reach under the mower you should disconnect the spark plug for safety. Now when you turn the blade by hand does the engine also turn? Is the blade bent? Is the blade hitting something under the mower? Tip the mower with the air filter side up and look under it and see what is hitting.

I have absolutely no idea what you just asked. Something metal squealed? How odd.