2003 Honda Civic Issue in Park

Yesterday my car was revving really high when I turned it on but I drove it up to the gas station, once I put it in park it would not come out of park. I was finally able to put the key in the gear shift to get it in drive and drive home. A friend who is a mechanic came over and "fixed" the problem which he said was the throttle cord (or something with the throttle) was stuck. I drove it this morning to work which is about 8-10 miles away and it was not revving the whole way here however once I put it in park again it started revving higher (not as high as yesterday) and I could get it out of park luckily. Also my brakes are really sensitive right now and when I am not braking my car seems to be coasting a little instead of just being stopped. Please help.