Head gasket

No overheating, no oil in water, no low coolant. Runs rough when starting cold then fine after few minutes. No white smoke. Mechanic says low pressure in cylinder number two. With no normal symptoms of blown head gasket, what else could it be? $2,500.00 repair. By the way had the heads redone, valve job, head gasket, timing chain, seals replaced two years ago. Had same symptoms prior to that repair also.