Mike, I am an experienced professional massage therapist, who also has PCS. When the bike rack came down on your wife's head, the impact also jarred her neck and perhaps even her shoulder.

The muscles of your upper back attach up into your head, so the two are connected directly. She may even have a whiplash type of injury, where the head goes forward and back rapidly and potentially moves the brain within the skull too.

I have treated this many times and experienced it myself. It takes time to heal, sometimes months or even years depending on the severity and how you go about treating it. I am experiencing shoulder/neck/head tightness and pain myself since my accident in March.

Things that could help:
Use an ice pack on the neck and base of head for about 15-20 min. You can also alternate with a heat pack.

Massage is the best thing for muscle tightness. The pain she feels behind her eye(s) is most likely referred pain from the muscle tightness, it is common to experience this and will go away when you do get the muscles to relax.

As long as there is not swelling inside her skull, you can take 2 tennis balls and tie them into a sock, then have her lay on the floor with her head resting on the tennis balls. You find the widest part of her ear and trace that place to the back of her head, that is where you place the tennis balls...her forehead will be higher than her chin.

Work up to 10-15 minutes, starting with a minute or two. It may be slightly uncomfortable as her head relaxes and makes changes as the muscles, etc find their way back to what is correct. Or, she may not feel anything at all, but more relaxed. Either is normal.

If possible I would recommend finding a local massage therapist who has experience with treating whiplash symptoms. All the muscles in her neck, shoulders, and back will need to be worked on, preferably once or twice per week, even if that means doing 1/2 hr sessions only to get the consistancy in.

Another fabulous option is to find a really good cranial sacral therapist...their work, if done properly, has the best benefit for PCS as far as bodywork is concerned. It is very gentle, but can be quite profound.

She can also use the tennis balls by rolling on the them to loosen her upper back. She can roll on the tennis balls with the groove between the them on her spine, so there is no pressure directly to the spine.
Tender spots are the ones that need it most. If she finds one, just rest on the tennis balls for approx 30 seconds and just have her breathe through to her tolerance.

Physical therapy is usually covered under insurance and they can help alot and assess her particular situation. Alot of physical therapists are now doing craniosacral therapy, so you try to find one that does this as well.

Yes, this will go away...perhaps in a couple weeks or longer, just depends on the severity she personally has.

If you have any questions, please don't hesitate to ask. Perhaps this will help others too.