Child Has Stiff Stomach, Breathing Difficulty, Communication Problem After A Fall. Is There Any Thing Serious?

Question : Thank you for your time. Back in XXXXXXX 2011 my 7 year old son fell onto his face whilst running at local training club. His fall saw him break his two adult upper incisors. In February of that year at 9pm one night, I went to check on him in bed and found him in complete distess, I was completely taken aback by his appearance. He look frightenly panicked, pulse racing, stiff as as board (stomach hard) , unable to breath, very erratic mannerism but was not very communicative, could not speak actually. After about 10 mins he indicated he was extremely thirsty and we kept giving him sips of water and also sat him up against pillows to help breathing, he was dribbling and spitting it out in disgust, sad he was going to vomit many a time. We were so frightened that we called an on-call Doctor (suspected anaphylactic shock) and he came out to us but a good 10 mins on again and by time the GP had arrived our son was reasonably back to normal, bar a complete loss of voice. He had no voice the next day or two either. This has happened a few times since at night but its come unexpected. However, during strenuous exercise like cross country training or even a game of football at school, my son experiences these exact symptoms again and has to stop, has sore throat, feels nausea, heart rate fast, he feels like in his words 'he is having a heart attack' and again the dribbling and disgust of ridding himself of this spittle in his mouth is terrifying to watch and so very upsetting for him, panic again with no sympathetic coach. We have had allergy tests and a stomach x-ray as we had suspected tooth fragments in chest, both tests showed nothing abnormal. We in Jun 2012 had a barium swallow and this x-ray also showed no abnormality of his oesophagus, stomach or duodenum. We have wanted to wait to see if these symptoms continue and a further year on he is still restricted by them. I have written to our Consultant Otolaryngologist to enquire if an Upper airway Endoscopy might be worthwhile as he had left things with us as parents to decide where to go. I wished to say also that these symptoms seem more apparent between our UK colder weather months of October to April, could temperature and weather conditions be relevant (exercise related asthma)? He seems very vunerable to the cold and always feels it more than anyone else, though he is of small frame but normal growth and height for a now 9 years, who is normal in every other way. He had colic as a baby or so we were told. He eats little and often as he explains he cannot swallow easily, so we chop everything up, especially sausages (perhaps fatty too?) During the summer it appears less troublesome to him. I would really appreciate some suggestions of what may be troubling him, we have considered Laryngospasm, GERD and are desperate to help him, if only I could film his symptoms and also ask if perhaps if there is a treadmill/exercise type test that he could perform to watch his symptoms and PH to see what might be the cause. We just wish to identify what it is and then this will help him greatly in coming to terms. XXXXXXX UK