Science Based Medicine is a movement to improve Evidence Based Medicine with a stronger focus on scientifically rigorous evidence. It's not in opposition to EBM.

To quote the SBM blog's about page:

"Good science is the best and only way to determine which treatments and products are truly safe and effective. That idea is already formalized in a movement known as evidence-based medicine (EBM). EBM is a vital and positive influence on the practice of medicine, but it has limitations and problems in practice: it often overemphasizes the value of evidence from clinical trials alone, with some unintended consequences, such as taxpayer dollars spent on “more research” of questionable value. The idea of SBM is not to compete with EBM, but a call to enhance it with a broader view: to answer the question “what works?” we must give more importance to our cumulative scientific knowledge from all relevant disciplines."

You can find the original Science Based Medicine announcement on their blog http://www.sciencebasedmedicine.org/hello-world/ and there's a decent bit of background on Pain Science https://www.painscience.com/articles/ebm-vs-sbm.php as well.