Advice? (Please?)

I dunno where else to really ask for advice on this, so...here I am.
For quite a while, I’ve been feeling a bit of uncomfortableness with my back. Haha, weird. It feels like I have terrible posture, and sometimes, a bit of pain. It feels like, at times, my spine is completely stiff, especially when I lay down on my back, and it’s only my spine. I feel nothing in my legs, or my arms, or anywhere else. It’s tolerable. I can still do every activity and ignore it. The only thing I really couldn’t do so well was sit up straight. That killed me inside, and I felt as if I always needed some form of support. I didn’t really see it as a big deal until I began to stress and try to figure out if something was wrong. Maybe it wasn’t supposed to feel this stiff? Maybe it wasn’t supposed to ache like this? I don’t know, since I don’t know crap on the subject. The only thing my doctor said was that there was a tiny curve, if that meant anything. Again, nothing to worry about.
But like always, my idiotic self decides to go on this huge hunt to figure out the worse possibilities. Like I honestly need to chill. I work myself up over every little ache, and thing I’m dying over a little bug bite.
Finally, I decided to kinda hint it at my mom. I brought it up yesterday, she didn’t really talk much on it. All she said was that she hoped it wasn’t the same issues my dad had. Oh yeah, my dad has back problems. If I remember correctly, he had something broken in his spine, and had to get it fixed with surgery. Now he has to wear a back brace, and is in constant pain. /Joyous/! (Heavy sarcasm, if you couldn’t tell.)
Because I wasn’t really satisfied with the answer, I brought it up again today. She said she could schedule a doctor appt. if I was really that concerned. Me, being the idiot I am, declined. I was honestly a bit nervous. I didn’t want to waste everyone else’s time on nothing, and have to face the fact that I was an idiot and I overreacted again. Sure, I might’ve been told that something was actually wrong, or have been told that nothing was wrong, and quit my worrying, but I really dislike being told that I was overreacting. I guess I’m a bit insecure on that? Dunno. I just hate myself for overreacting, and I kinda hate it when others pretty much tell me that I was overreacting. I hate that about myself, which is even how I get into these situations.
I don’t know what I should do, honestly. Should I just suck it up, live with it, and tell myself nothing’s wrong, or tell my mom tomorrow that I would like a doctor’s appt. (after school, duh, so she’d know that I’m not just doing it to skip school) about it, and see what’s wrong, or something else?