Diagnostics - for the movement apparatus we know: functional before structural diagnostic procedures

For 80-90% of complaints out of the movement apparatus more or less complex functional disturbances are responsible and not structural destructions like rheumatic kneejoints, osteoporotic fractures or nerveroot swelling in disc prolaps. But we medicine people learn to >90% of our education and specialisation facts about these spectacular diagnoses including carcinoma, inflammation, fractur or marked neurological deficit. 
So its not really surprising that the common diagnostic procedures were developed to reveal structural changes in the tissue. So it is state of the art, to diagnose fractures with X-ray, bone metastases with the CT and bonescintigraphy or disc changes with the MRI - and in these diagnoses it should stay like this! But in the movement apparatus the dangerous "red flags" luckily occur just in <5-7% of all people having strong pain.
The lion's share of pain is caused by overload of muscles, ligaments, tendons, capsules, joint blockades or crampy muscles.
The pain receptors are not mainly located in the bones, discs respectively in the nerve itself. They have the largest concentration in structures out of the soft tissue - ligaments, capsules, tendons, fasciae, etc. But up to now there is no single diagnostic method to make the pain receptors visible - except of animal dissection studies performed by specialized labs.
But this doesn't mean that some of the most common pain diagnosis can be less painful than an acute discprolaps! 

"The intensity of pain correlates very rarely with the severity of the cause"

Prof. Bigos, one of the "big" scientists in the field of spinal disorders, stated that degenerative changes can be rated as grey hair or wrinkles in the face - just normal body expressions of getting older, which have mostly no clinical relevance. Much more important for the progress of back pain are relieving postures and movements as well as fear avoidance beliefs and behaviour. These pain-behaviours very fastly lead on to decreasing muscle strength in the large, superficial and the small, deep stabilizers of the spine.
The decrease of strength in the small and deep segmental stabilizers is responsible for becoming more unskilled, what increases the risk to hurt the back again during unexpected fast movements, like stumbling. This knowledge had the consequence that the necessity of a measuring method for the musclestrength in all 3 planes stood more and more in the center of clinical research. About 15 years ago western specialists developed high-tech-machines to measure maximum strength and strength endurance compared with the strength values of healthy subjects of the same age, gender, height and weight. With the same devices the trainingtherapy can be performed afterwards, where one therapeut cares just for a maximum of 2-3 patients at once. With this intense-care-model not only the result is fine (about 90% reach their healthy strengthlevel again!), the 12-week strengthening course is also very safe!