Rattling behind the fret im pressing

There are three common causes. It may be that your nut slots are cut too low. Or it may be that you don't have enough relief in the neck. Or it may be that you have one or more high frets.

Start by looking at the relief. Be sure it is set correctly providing enough relief. Then look at the clearance of the strings over the first fret when fretting between the second and third fret. There should be a bit of clearance there. If your strings are touching the first fret, the nut slots are cut too low.

It's not likely that you have a high fret if you don't have buzzing issues on the bridge side of the fretted string, but it's possible. I'd check the other two things first.

 

ah, the dreaded "back-buzz"; elusive and unpredictable.

+1 to turnaround's three factors; too-low nut slots, too-straight a neck, random high fret back there somewhere.

 

Yep, I agree. And I also think that The Dreaded Back Buzzers would be a good band name.

 

Stop pressing on the fret. You're supposed to press behind/in between the frets.
Or, if you're already doing that, your nut slots are cut too low.

 

Take it too a good luthier! They know what to do; have the skills, experience, and tools that you don't.

 

Turn your amp up.