Why is it sumtimes hurtful for me to breath?

Sumtimes if I lay in bed or I'm at school, my lungs kinda tighten and Hurt. Then when I breath, it kinda hurts and I feel like I will either hyperventilate or pass out, but it never happens. My windows r always open and I'm always outside so idk y it hurts. I don't think it's asthma cuz I never had an asthma attack or anything. I don't really have shortness of breath, it just hurts. I'm scared to tell my parents cuz a lot of times if I'm hurt or sumthing hurts, they think I'm acting dramatic and ill. Its not pollen though. I'm thinking about asking my doctor at my next checkup, but that's in like December... Pls help. Does anyone know any way that I can make it stop hurting? Like sum trick or theory or sumthing that may make me feel a little better (besides medicine or anything)?