I found myself completely lost on this hand after he called my flop bet. I don't know why but I had no idea as to what to do on the turn. I ended up check calling and then found myself in the same predicament on the river.

Villan is a decent regular. He runs about 24/20

PokerStars No-Limit Hold'em, $4 BB (5 handed) from (Format: FlopTurnRiver)

UTG ($520.90)
MP ($733.85)
Button ($400)
Hero ($659.10)
BB ($390)

Preflop: Hero is SB with A, J.
1 fold, MP raises to $12, 1 fold, Hero raises to $58, 1 fold, MP calls $46.

Flop: ($120) 3, 4, J (2 players)
Hero bets $100, MP calls $100.

Turn: ($320) T (2 players)
Hero checks, MP bets $155, Hero calls $155.

River: ($630) 6 (2 players)
Hero checks, MP bets $420.85 (All-In), Hero????

Yeah if you call turn you have to call a blank 6 on river, which is probably what I would've done. I think this is a good chance he has 10s but I think he turns up a flush draw often enough to make it profitable.