You could experience back pain or leg pain with endometriosis if the tissue grows all-around your spinal nerves. We then say an individual has amplified neural tension. Physios and doctors can easily test for elevated neural tension by obtaining you to carry out certain movement exams, e.g. the slump examination https://www.theorthopaedicandpainpractice.com/treatment-options-for-lower-back-and-knee-pain/