u/Decent-Problem4543

Hi! Just started cycling, I'm finally getting used to the seat, but my struggle right now is my back pain. I just did a 12 mile flat road bike ride and man, my back killing me! When I'm riding, I often have to set up right and stretch a little bit to, I don't even know how you describe it, but I just feel more relaxed when I sit up right. I'm hearing that it might be my posture or the my bike size is too small? Probably going to take it to my shop to find out, but wanted to hear some other feedback as well. Thx!