I'm sorry, I'm having difficulty understanding what you're asking or if you're just venting (which is fine/ok too!)

Actually, all that sounds pretty reasonable to me. Narrowing, stenosis, osteophytes (bone spurs), arthropathy (arthritis) degenerative disc disease.... these and other things ARE common as we age; they're part of the price we (as a species) pay for walking upright and having developed brains so smart as to increase our lifespan by about 100% (in the last couple centuries). Many/most people are walking around with these same things, and feeling fine and in no pain whatsoever. Others of us are not so lucky, and some are worse. The reasons are complex and unique. Genetics, jobs, activities, medical histories, and other factors all go into why some people are affected differently than others, and we're still a long way from knowing all the reasons and answers.

Physical therapy is the gold standard for firstline treatment; more than 50% of patients get some relief from it. Being careful when doing any exercise is good advice, and even better when we have conditions that can be aggravated by overdoing/overuse. If she prescribed some pain medication, count yourself among the lucky; many doctors won't do that at all anymore. The pain medication may be meant as a stopgap - something to help you be more comfortable at least until something else can be found to help or be done.

MRIs are like any other static image; they are a snapshot in time. Things can and do change, and some things may not be caught/noticed the first time around, or the doctor may want additional imaging (locations, positions), or imaging with contrast, to better see what's going on in order to decide what to do next.

Am I missing something? (Very possible)

Doc