K., go to webMD for advice. Rest, heat, ice, and lots of different rubs work. May need to use a pain killer like acetaminophen too. It should stop hurting after a few days if it is a pulled muscle. For your own peace of mind, you may want to call your doctor's office and speak with the nurse who can advise you rather than make an appt. right away. I have had many pulled muscles. Sometimes I barely move and they pull. It's because I don't exercise every day.
I would suggest some exercises in the morning to warm up your muscles since you have a young child. Don't exercise that back muscle until it has healed unless the nurse says it's ok. Regardless, if it hurts at any time, stop what you are doing and rest it. If she is old enough to get into the swing, etc., with just a little help from you, then let her do these things for herself. Otherwise, do "core" exercises to strengthen your abs because those are the muscles that really protect your back. I have a very bad back but since I went to a Physical Therapist last year, it has been much better. I learned exercises to strengthen my "core" and how to walk properly up and down stairs. Now my back is much, much better.
There are some good "ice" products available at drug stores. I bought one large enough to cover my lower back. It stays very cold, I keep it in the freezer so it's always ready.
I hope this helps and that you will soon be feeling better.