Allsorts: do you know for certain that pollen is the only thing you are allergic to?
People can be allergic to practically everything, and the symptons you describe sound like mine.
I am not allergic to pollen, so I can't advise there, but I am allergic to formaldehyde which is used as a preservative in cleaning agents, shampoo, probably make--up as well, and certainly was used in nail varnish, plus house paint and varnish. It is also used in making a large range of synthetic fibres.
I itch madly if I am stupid enough to wear polyester, sit beside someone whose soap, makeup etc. makes me sneeze, so I would suggest you start by going through your wardrobe and only wear natural fibres for a month, making sure that you wash your clothes in evironmentally friendly and allergy tested laundry detergents and never, if you dry them in a tumble dryer put sythetic fibres in at the same time.
If wearing only natural fibres doesn't help (presuming that you know you are not allergic to wool!) then try checking colouring agents and preservatives in food and cut out anything that has too many additives, and preferally any vegetables that have been grown using artificial fertilezers.
It is a long hard road, and you will need to keep lists of what you have discarded temporarily from you wardrobe or your diet.
Unfortunately, if you use perfumed soap powder, fabric softener and toiletries you will need to wash your clothes at least three times before there will be no traces of these things left in them,
However, if it is perfume, additives etc. that you are (also) allergic to, it will pay to go through this infuriating "treasure hunt".
Forgot to say: wash your washing machine on the hottest cycle without any clothes in it, and only washing soda or vinegar in the soap tray before you start the great wash of your clothes and bed linen, and clean the filter of your dryer well too.