Rattling

I hear a rattling sound when in idle and under acceleration, it gets louder the more I accelerate. I removed the serpentine belt to see if it were any of the pulleys, but the rattle is still there. I was touching all over the engine with a screwdriver to see if it will help pinpoint the rattling. I started to feel the rattle in my hand when I put the screw driver on the oil pan and felt it more when I put it above the oil pan. I used some tubing to act like a stethoscope and was able to hear the rattling the loudest and clearest above the oil pan as well. So I feel pretty confident about it being in that area but I am not 100% sure. I blew a head gasket in February of this year that was caused by overheating from a cracked radiator. I took my engine apart and did it all myself. I put a brand new alternator, water pump, throttle body in as well when I did the repair. Has been running great since then. I know i need to change my motor mounts pretty soon because of some engine vibration. I do not think I want to take my engine apart again so I might take it to the shop. Does anyone have an idea of what it can be and if I should do it myself or take it to the shop?