Did a "pro" shop do the brake work?? If so, it needs to go back and be looked at again, this description mimics a typical midas "brake job" without the lifetime guarantee! And I'll bash midas and all midas franchisees until I'm in my grave.
Were the rear brakes serviced? Were the rear wheel cylinders serviced/replaced? The parking brake condition can have many causes from shoes worn beyond limits, stuck/non-func "automatic" adjusters, a park brake cable semi-frozen (non-lubricated) on one side, etc. The parking brake cable must be periodically adjusted also as the rear brake shoe wear, then re-adjusted when the shoes are replaced. That includes verifying the parking brake "balance" connection is functioning properly so both sides are equally applied.
If you meant to say..."the brake warning light" comes on, then that is an electrical issue. The "warning" light is controlled through the proportioning valve and if the switch was "tripped" before the front brakes were serviced, then it either needs to be reset, or possibly the plunger on the switch sheared off (very common) and now the warning light is permanently "on".
If you meant that the "brake lights come on when I turn on the headlights", then that is also an electrical issue.
A "low" brake pedal can be related to many issues. Some of which are poorly bled hydraulic system (did the service point bench bleed the replacement master cylinder?), or a booster push rod that was not properly adjusted for the replacement master cylinder (very common!!!!). And of course, the rear brakes May have not been initially adjusted manually if replaced.
One additional item I see constantly...replacement master cylinders (both new and remans) seem to never have "residual pressure valves" installed in the outlets. Thus...even if new master cylinders, calipers, wheel cylinders, etc. Are installed and bled properly, pedal travel will always be excessive and power brakes will always be "touchy" like a toggle switch.
