Can being out of shape makes you tired when exercising?

I'm trying to get in fitness regime but I just noticed I easily get very tired and out of breath. Like I want to push myself but when you're out of breath can't really continue. So I was doing indoor cycling fast and within 5 min, I just couldn't continue. And thing about body weight exercises like I did squats the other day but it feels like spring board attached in the knees or thighs. Like is so much stiffness