Early 2011 MBP Hard Drive Noise - What IS normal?
I can tell you, this isn't normal.

You shouldn't hear the hard drive very much at all, and only a little chatter when you're using it extensively.

Since you've clearly established that it's a hardware problem (because pressure fixes it), you should probably try to get it fixed. Rather than open the machine and do it yourself (violating your warranty), you should get Apple to fix it.
Since your computer is pretty new, it should definitely be a free repair.

You can take it to the Apple Store and tell Apple what happens. They'll take it and do some tests, then replace the drive (or whatever part they think needs it).

Make sure you back up all your data first; you won't get your old drive back.