You should always talk to your doctor if you have any kind of persistent problem. Internal allergy possibilities are no exception.
ask a doctor
Yes, you're doctor can perform an allergy test. With an allergy test, your doctor will prick your skin with a very small sample of different foods you could be allergic to. If you have a reaction, then you've found a food you are allergic to.
it is not normal. you should visit your doctor it is not normal. you should visit your doctor
Glutin allergy
There is a possibility that you have a glucose allergy, but the only way to know for sure is to go to the doctor and get them to do an allergy test.
Food allergy testing can be done in the doctor offices. If you cannot get to one try the free clinic to see if they could do it for you.
It is wise for you to see your doctor. If you are allergic to oats you could well be allergic to wheat, bran and rye and this is called 'Celiac Disease' which is an Auto Immune System Disease. Have your doctor give you a test to Celiac Disease. If your doctor finds you only have an allergy to oats then you can take Benadryl for it. Beware .... Benadryl can make a person feel very sleepy so don't drive or operate machinery.
For a cough caused by an allergy you take an over the counter cough syrup and an antihistamine. If this does not resolve the problem go to your doctor.
You may have an allergy. If not go see a doctor and they can tell you more.
dust your furniture and vacuum regularly
A general practitioner (family doctor) may be able to, but the specialist would be an allergist.