Thanks a lot for your input. I am sorry to hear about your problem. I am going to address your primary concern but later you can ask anything you want. I am myself an associate professor of ENT and specialist in dealing with an allergy. Negative testing doesn't rule out allergy. In your case, allergy is possible because sneezing is the primary symptom of allergy. Sometime we can't check against all the allergens but that doesn't mean that you can't have allergies. Your symptoms are consistent with allergy and sinusitis. So I will address your question in two aspects; what you can do yourself and what your doctor can do for you. As far as what you can do yourself is concerned in such situations you can use following over the counter available products;
1. Afrin nasal drops, 2 drops thrice daily for 3 days.
2. Tablet Benadryl twice daily for 7 days
3. Nasacort nasal spray, 2 puffs twice daily for a few months. Please use the spray because that is the first-line treatment for such a case.
4. Tablet Aleve 500 mg twice daily for 5 days.
5. steam inhalation with menthol drops twice daily for a few weeks.
If the symptoms persist after 2 weeks, see your ENT and proceed accordingly. There are many other things which can be tried. There is non-allergic rhinitis as well in which ipratropium bromide helps but in that sneezing is not associated. I reassure you that there is nothing serious and you are going to be alright. Lastly, I would like to share a home remedy. Take 250 ml of honey, add one tablespoon each of ginger extract and black pepper. Make a solution and take one teaspoon twice daily. It might take 7 days or more but will help you. I wish you good luck and that you get well soon. My goal is to provide you with excellent service – if you feel you have received anything less, please reply back as I am happy to address follow-up questions. Kindly rate me when you are done. You can come back here to ask anything even after you have rated the answer. I will be glad to help you always. A 5-star rating is requested and will be appreciated. Regards