welcome to the world of pins! , good suggestions above! even a nib will need some tweaking now and then and a small selection of tools and supplies is a good idea, , including at set of 4 hollow shaft hex driver(1/4, 5/16 , ? 7/32 and 11/32? ) for the flipper pawl a 3/8 drive ratchet and a 6 mm or 8mm hex head is needed , a few small screw drivers maybe a soldering iron , some microfiber towels , novus one for cleaning and some blitx wax or similar and you have most of what you would need.
you might try moving the sticky flipper up and down manually with the glass off it may unbind it, as well see if you can slide a credit card underneath the flipper if no it needs to have to have the flipper/playfield gap increased by loosening the pawl nut as above,
this is likely an easy fix and you will be playing in no time!