4 inch barrel.
.357 seven shot or .44 magnum 5 shot?
Seven rounds 158gr or 5 rounds 240gr?
Go to a firing range (where rentals are allowed) and fire both.
A lot of people preach the .44 as if it is the minimum bear cartridge (within the pistol world) worth considering. But even for people who are competent shooters and are in good shape, the recoil on the .44 is quite significant, and that issue is exacerbated as you decrease the weight of the .44 pistol. Personally, I don't like doing any extended shooting with the .44, especially without gloves (the cartridge can literally pivot the pistol right out of your hands if your grip is compromised, like sweaty hands). Yeah, I know the old adage: you only need to be worry about 1 shot, because a charging bear will be on you before any follow-up shots are possible. Whether or not that holds true for all bear encounters (no 2 encounters are the same), you will definitely want to familiarize yourself and practice with whatever sidearm/cartridge you choose. .44 mag ammunition is more expensive and the recoil is not pleasant for extended range sessions. If you’re okay with those drawbacks, go with the .44 mag.
If not, go with the .357 mag. Before the invention of .44 mag, .357 was widely regarded as a capable wilderness defense cartridge (it was used to fend off bears and dispatch dangerous big game). And despite the arrival of more powerful cartridges, it’s still very capable for such duties. Recoil is still substantial compared to the regular self-defense cartridges (9mm, .40), but it is certainly more manageable than .44 mag and the other big magnums.
Truthfully, your chances of running into a black bear, much less one that is aggressive enough to attack you, are very slim in the northeast. Bear spray works, in most situations. Otherwise, if you already have a self-defense pistol chambered in 9mm, .40 or .45, you could look at getting ammunition that is better optimized for hunting. None of those cartridges are preferred for tackling big game, but they can work in a pinch with the appropriate ammunition and good shot placement.