Juba,

Both forward flexion and sneezing increase intrathecal pressure and can be irritating to discs. A disc is the most common source of lower back pain in both sexes and in people under the age of 55. Epidemiology studies show that it comes in at a whopping 40% followed by facet mediated pain (where is usually aided by flexion not aggravated) and SI mediated pain (which very rarely travels above the L5 spinous level). The position you get stuck in following your episodes is called "antalgia" and is commonly seen with a discal injury as well. There is also the potential that you have a menescoid entrapment (little window wiper inside the Wikipedia reference-linkfacet joint gets stuck outside the joint and squished... very sensitive and very painful) this too can cause antalgia. Facet mediated pain, however, differs from that of a disc in that it is usually accompanied by sensitivity of the overlying spinal tissues (they share innervation through the medial branch of the dorsal ramus) is your spine sore to touch? Please also don’t think that a discal injury can’t have a concomitant facet component as well, as this is also quite common and complicates the diagnostic process. Given the chronicity of your issue and constant recurrences an Wikipedia reference-linkMRI is warranted to rule out anything more sinister than the above. I would also recommend seeing a good manual therapist who has the ability and training to both manipulate and appropriate a exercise program that will reestablish stability and proper neuromuscular control of the area in question, as both of these conditions I mention are brought about by poor proprioceptive reporting in this area. Your exercises need to be customed to your case and sometimes they can flare a condition… Don’t throw the baby out with he bath water. Your therapist should modify these for you and find easier ones until you reach a level of competency and then move you onto a more difficult progression.

Cheers, SPPAWA