Doctors define lower back pain broadly according to three categories. 1) Acute lower back pain is generally defined as lower back pain that lasts for five weeks or less. 2) Sub-acute lower back pain goes from five weeks to three months. And when doctors talk about 3) chronic lower back pain, they're talking about back pain that's lasted for more than three months. Acute lower back pain generally self-resolves.
When Should I See a Doctor for Acute Lower Back Pain?
Most of us, at some point in our lives, will wake up with a case of acute lower back pain. You wake up, your back hurts. You twist or turn and you have an episode of lower back pain. Depending on how severe that lower back pain is will depend on how urgently we seek medical attention. If the pain is really bad - even though that pain will still go away within a couple of days, a couple weeks, or certainly by five weeks for the most part - it still is advisable at that point to go and see a doctor go get checked out. Also, doctors have a lot of tools in our toolkit to take away pain faster than it may have otherwise gone away, starting with oral medications, topical medications, and so on.
When acute lower back pain is not severe - when it's more of a mild or moderate ache or it's bad for a few hours then it goes away - often it can be managed at home with ice. We generally say that for the first 48 hours it's a good idea to use ice. After that, heat or ice. Doctors who treat back pain and other joint pain get asked all the time, "Should I be using ice, or should I be using heat?" A general rule of thumb is for the first 48 hours to use ice as probably a little bit better. In truth - in terms of long-term outcome - it really doesn't make that much of a difference whether you use ice or hot, but for the first 48 hours, it makes sense to use an anti-inflammatory, like ice. After the first 48 hours, patients generally tend to say that heat makes them feel better when they put it on. Ice tends to work as an anti-spasm on it. I usually tell people to use whatever makes them feel better.
And then there are topical over-the-counter medications and oral over-the-counter medications. Topicals like Icy Hot®. Oral over-the-counters, like non-steroidals, like ibuprofen, Advil®, Aleve® and then there are the acetaminophens (Tylenol®) that work more as analgesic. Sometimes taking an over-the-counter oral medication - assuming no contraindications - can help just getting through the first couple of days, assuming the pain is not that bad.
When people have acute lower back pain that it's not that severe that they seek medical help, I still recommend - even if they just have a few days of acute lower back pain and they're not sure why, but it just came on - I think it's a good idea at that point. This is one of those times when I think it's important to remember that "an ounce of prevention is worth a pound of cure." This is a good time to go see a doctor, get checked out, ideally get hooked in with a good set of physical therapy exercises that you can learn in a short amount of time and incorporate into an overall exercise regimen, which will just make it a lot less likely that you have another episode of acute lower back pain in the future. It just helps to protect the back in the future and, ideally, helps to prevent a lot of problems down the road with the back.