I'm not sure if it is a health condition and feel more like a psychological disorder. Please do not feel offended, I mean good. Have you tried to do anything to find what relaxes you? Are you carrying too much stress with you to the bed? Like, your job or your studies or your social relations, etc. Do you have a good pattern of sleeping like .. sleeping at the right time (10 pm, etc) and waking up at the right time (5 am, etc)? Have you tried meditation or deep breathing before hitting the bed? There are many such questions that you can ask yourself and if you calm your mind and relax and think over why are you having this disorder, you might find an answer. Do you go for jogging or for walk in the morning/evening? That will "definitely" help.
If it is a psychological problem, your brain is tuned to react that way whenever you tell your brain that you are going to sleep. Try this little activity before sleeping. You can try this activity any time of the day.
Relax yourself a bit. If you have to go to the toilet or need to take a shower, do so.
Forget about work, job, kids, studies, etc etc. Keep all of that aside for some time.
Sit down and breathe deeply. Inhale life into you and exhale it slowly. Over and again until you are extremely relaxed. Relax enough that it makes you feel that the time has stopped and everything is calm around you. Keep your eyes closed and inhale deeply and then while exhaling, make a humming sound. This may feel funny but it works wonders if you do it correctly. Trust me, you'll see the benefits of doing this little activity.
Inhale and exhale air while humming. As you keep doing this activity, you will begin hearing your humm louder in your mind. As you spend about 5 to 10 minutes, you will begin going into a sort of equilibrium. Once you feel that you've hummed for a while, simply inhale and exhale but this time, a little faster than before. begin inhaling and exhaling just like you normally breathe but "continuously". Begin inhaling/exhaling a little faster like a pendulum .. in and out. Keep picking up pace as you go on inhaling/exhaling. And if you do not have any heart condition, go as fast as you can until you feel you cannot inhale/exhale at that fast pace.
And when you are done, just slow down with inhale/exhale and come to normal eventually. keep your eyes closed all of the time. Do the humm thing again if it helps.
You just have to try some yoga to calm your mind before hitting the sack. Please stop alchohol, smoking, drugs, etc (if you are into that stuff).
Inhaling/exhaling air is a HUGE stress buster! It works wonders for me and so can for you :)