Breathing problems: Car crash related?

My 13-year-old son says that when he lies flat on his back he has difficulty breathing, but he is fine with a pillow under his head. We were involved in a car accident last year where he had seatbelt injuries and I wonder whether it could be anything to do with that. He is not keen to go to the doctor as he thinks this will involve having tests/scans (which he had a lot of after the accident as he suffered from double vision). Should I take him to the doctor despite his fears?

Dr Fred Kavalier answers your health question:

I think it is unwise ever to dismiss the symptom of breathing difficulties, without at least thinking carefully about what might be causing it. I assume that your son is able to carry on with the normal activities of a healthy 13-year-old without any problems. The car accident sounds like it was quite serious (double vision is another symptom that should never be dismissed). If he had seatbelt injuries, it is possible that he may have injured his neck, or his voicebox or even his windpipe. The belt might well have crossed your son's neck if he's less than 5ft tall. Having said all of this, I find it difficult to image what kind of injury would cause breathing difficulties when lying flat, but no problems when standing upright. I think it would be wise for him to see his GP, who will decide if he needs further tests.

Please mail your questions for Dr Fred to health@independent.co.uk. He regrets that he is unable to respond personally to questions.