Ugh; pain like an old lady

I  tweaked my back yesterday afternoon doing something silly, and I'm still suffering for it today. I could barely sleep last night, and only in a position for a couple minutes before shifting and turning. I'm a bit better today, in that I am capable of sitting for more minutes than I was yesterday, but I'm still in a bit of an ache. All this happened because, of course, I have little to no strength in my core muscles. I'm working on that, as of yesterday, when the stretching and exercises have been therapeutic. All I need to do is keep up with them, and I'm in good shape.
If you can believe it, I've been keeping track of my calories for more than a week, and I've only been over my goal once since then. Even today, eating with the family, was an under-calorie day.
Daddy is bringing a bike for me with him in a couple weeks, and I'm super excited to start riding it around the neighborhood. There's a woman who walks around our streets, on a loop. for about 20 minutes every day about mid-morning. I figure I should be able to do that and more on my bike, and add to my hiking exercise. I'm not one for riding around on city streets, but going around my neighborhood, which does have an incline along a portion of it, should help me quite a bit.
The problem, you guys, is that I don't exercise enough, and the more ways I can do that in fun and engaging ways, the more apt I'll be to do it. Hiking and biking are my jam.