Head pressure in temples and behind nose.

I've been having head pressure in my head since September 09. I just woke up one day and my head started feeling like someone was pumping it up full of air/pressure. If I go up stairs or walk fast or jog my heart starts to race really fast for no reason and I feel it thumping in my head and the head pressure becomes worse.

I used to exercise all the time and be very healthy. I'm not sure why I can't even exercise anymore. My head starts to pressurize and it changes from a pressure to head pain. I've noticed I have a lingering dry cough the whole time and it feels like something is moving/draining in the back of my nose. I've had head MRI's and blood tests and chest x-ray's all coming back negative.

What could be causing this? I had an accident in august where I wasn't wearing my seatbelt and was t-boned at high speed. Could I have damaged something in my spine? Or is this a virus or something totally not related? I'm trying to narrow it down especially since my throat feels dry constantly and it feels like something is constantly irritating my throat and making me cough.

My heart speeds up and makes the pressure worse if I stand up or perform strenuous activity. Is anyone else experiencing anything like this?

[remar]

It sounds like a sinus infection but if you've been to the Dr they would have picked up on this. It could be allergies so you may want to be tested for that.
I would have more testing done that concerns your car accident. Your problems started after that.
Are you having any neck pain? I'm thinking whiplash possibly. If your neck or spine is out of place it can cause all sorts of problems. So you may want to consider seeing a Chiropractor.
Sorry I could'nt be of more help. Take care. Remar