I drive a 95 integra ls and I checked the compressions of all four of my cylinders because it was running like crap.

1st-120 2nd-125 3rd-120 4th-140

Is this at normal compression? I was kinda thinking they're way too low.

How do i fix this? Change the head gasket?

Is changing the head gasket easy?...costly at the shop?

HELP!!
Thanks