My car once had the same problem. It's not a Honda but I was at a stoplight and when I put the clutch pedal in and tried to put it in gear it wouldn't go in and then I realized that the clutch pedal was stuck to the floorboard and I had to take it out myself. If this is your problem, then I must warn you that you have to replace the whole clutch system in your car. Even if the clutch pedal is not sticking to the floor board, if the gears don't want to go in it is most likely that you're clutch system has expired. Go have it checked as soon as possible. Getting a new clutch system should be in less than 250 USD