I been using azelastine and i always have the bitter taste and swallow it. is it ok? is there harm swallowing it? when i spray its alot hard to use

No harm: swallowing it, and bitter taste is a common side effect, read the product insert on correct way of using it, mainly spray straight backwards into your nose not upwards, communicate your concerns with the prescribing physician on follow up, take care

Change technique: Be sure to aim the nozzle towards the sides of the nose and not the center. Avoid inhaling while spraying despite what the instruction told you in the package insert. Tip your head forwards for a few seconds afterwards. This may help reduce the amount of spray entering your throat and thus the taste. Let me know if this helps.