Sometimes pain can make us feel nauseous, so it's a reaction rather than a symptom. I've not had what you're describing, but when I've had injuries that can't possibly impact my digestive system I've felt very nauseous. It may be that the pain is impacting your body in some way, and your body is reacting by feeling nauseous.
In your position I'd ask my doctor if I could take travel sickness pills for a week or two to see if they helped, but I'd not try that without the doctor's agreement.
