BTN is 47/5/3, no stats on SB but he seems fishy.

$0.25/$0.5 No Limit Holdem
5 players
Converted at

Stacks:
UTG ($49.55)
CO ($49.55)
BTN ($26.50)
SB ($87.80)
Hero ($72.40)

Pre-flop: ($0.75, 5 players) Hero is BB [7h]
2 folds, BTN calls $0.5, SB calls $0.25, Hero checks

Flop: [7c][Js] ($1.5, 3 players)
SB bets $1.5, Hero calls $1.5, BTN calls $1.5

Turn: ($6, 3 players)
SB bets $3, Hero calls $3, BTN calls $3

River: ($15, 3 players)
SB checks, Hero checks, BTN goes all-in $21.5, SB calls $21.5, Hero ???

Not raising the flop is pretty bad here imo, I guess you were trying to encourage the button to come along but I'd rather hope SB has a 7 and we have him outkicked. I feel calling looks like the clear option at first, but I find there's just too many turn cards which make us think "Wait, did he just fill up?" or the board can pair or what have you. It's hard to get money in the pot if he is decent without a seven anyways, hence look at how incredibly awkward the turn is.

Not to mention, people just aren't willing to fold jacks and usually don't lead bluff. That's why we don't raise the sb with air here.

I have no idea why you checked the river, this is a value bet 100% of the time. I would be tempted to overshove the SB, as I don't see what c/c the river that has you beat, he probably has 7T or something. Yeah go all in.

Raise somewhere, please.

I don't mind the flop call at all (since there are really no draws out there), but you really need to pump it up on the turn to prepare for your river shove.