Let it break in some more. Just baby it around for a couple hundred miles more. Maybe that noise will quiet down some. I don't know why your oil pressure is that low using the info you have given. As long as you have 10 psi. for every 1,000 RPM you are okay. You could use thicker oil and the pressure will go up some. Try some 10W 40 next oil change.
Oh, speaking of which, did you change your oil after intial break in. That could be your problem. The assembly lube etc. could have clogged the oil filter enough for that to happen.