Back problems

So ever since I was pregnant (I have a 18 month old) every time I sit for a long period of time my back really starts to ache, and if I tense my hips my spine will crack in several places, mostly in my lower back though. Anyway after i gave birth my back felt a little better for a while, but a few months ago it got worse again, I dont know if it's because I'm not as active as of late, recently I've been going through a lot, and I tend to stay inside and watch Netflix, and I sleep more than usual now. So I'm thinking maybe that could be a cause of the more back issues, I'm trying to make an effort to get myself back on track now though, and in the mean time is there anything I can do to like help my back pain? its mostly in my lower back. I dont want to even be able to tense my hips to crack my back anymore, , I dont want to move a certain way and have it crack. I want the aching to go away, I'm going to try to avoid a chiropractor, or a physiotherapist. I'm thinking more of excersises or yoga that targets stretching out the lower back