Welcome back!
Your gear is OK for level 87. You will want to pick up some better gear by level 90, but that will happen naturally.
The way forward for now is to keep questing. You can also optionally queue for dungeons and/or battlegtounds. They won’t speed you up much, but may provide a change from the routine.
Things are scaled now, so wherever you go within your level range, all mobs will be the same level as you see them. So you can change zone if that helps. If you go to Stormwind now, you should get a quest to start the Mists of Pandaria expansion. That might provide a change of scenery. Cataclysm and Mists have been merged in level, so you can do either.
At level 90, if you go to Stormwind, you will get a quest to start the next expansion, Warlords of Draenor. This has a long introduction which is quite fun the first time you do it. You will be told to report to the Dark Portal at the Blasted Lands. Pro Tip: when you get to Blasted Lands, there will be a half-dozen quests near the Flight Master that will give you some excellent gear pieces, so it’s well woth diverting to those before you go through the Portal. The difficulty ratchets up for a couple of levels around 90-93, so you’ll be glad you did.
I’m not quite sure what you mean you don’t know whether to PvP or raid? You can do both. Or do you mean you’re not sure you want to do either? Dungeons are also possible, and can be repeated to a very high level now, on par with raids.
The game has been mostly about max level since The Burning Crusade, but it is much more about max level now than it was in Cata.
What is it you want to do in the game? What do you enjoy in other games? Maybe we can help you get toward something you will enjoy.
Here are some website resources that might help:
https://www.wowhead.com/ for anything about gear or quests or items
https://www.icy-veins.com/wow/beast-mastery-hunter-pve-dps-easy-mode for the basics of BM hunter as it is played in BfA.