my kitchen faucet is clogged with something because sometimes it works fine and then all of a sudden nothing

this has been going on for a few days now. I took off the filter , no difference. whatever is clogging it is only doing it sometimes. I can't figure out how to take the spout off and I am really at a loss as to whether to call a plumber or not. Don't want to if it something I can fix. help please