While an SLP can be very helpful for TBI issues like aphasia, apraxia and stuttering, your issues sound like they might need attention from a neurologist or physical medical specialist.

As a fellow sufferer of a severe whiplash, I agree with Mark that the issue is in your neck. It could be structural and/or nerve damage/impingement. It might be a good idea to see a neuro and have an MRI of your neck.

After whiplash, it takes a long time for all the swelling (internal and external) to abate. As it does, you may find that some of your symptoms improve.

One other issue that can impair swallowing, and is fairly common is whiplash, is dry mouth due to nerve damage interfering with the saliva glands.

Of the three gland around my bottom jaw, two don't work at all and the other has very minimal function. For many TBI patients the problem is further exasperated by medications that cause dry mouth. My mouth is dry as sand and that makes it hard to speak and swallow. I use artificial saliva spray to help mitigate the problem.

After whiplash, it can be a good idea to see a dentist who specializes in TMJ, etc... In the interim, you can test the glands yourself. Take three small cotton balls. In turn, put one in the front of your lower jaw, and push it down between your gums and the back of your lip. Put the other balls in the same position, just one either side of your bottom, front teeth. After a few moments, if all is well, they should be quite damp.