Back pain, insomnia, and toddlers

I am almost 22 weeks pregnant and I am pretty sure I am having sciatica pains in my back and my hips hurt and my pelvic bone is struggling. What are things I can do to help with these pains. I never had this issue with my first pregnancy and chasing around my 2 year old is now quite difficult, I hobble around when I walk and my belly is quite large I have gained less than 15 pounds my entire pregnancy but I am just huge and really starting to feel like I’ve been ran over. Please help I have quite a ways to go before the finish line!