Tennis elbow, and elbow pain in general, is the kind of thing that can hurt for weeks, days, months.....and years and decades.
Mostly the pain isn't that bad, it's an annoyance, or a problem one can live with. That's how it goes, time passes and the pain becomes normal....it comes and goes....and then we realize it's been hurting for years.
Another common experience is that our elbow/forearm hurts over time...and we 'try' to fix it.
We stop doing the the activity we love (sport, hobby), or what we have to do for work for a while, things feel a little better, but comes right back when we start up again.
We go see a doctor and do what they tell us to do: anti-inflammatories, more rest, corticosteroid injections, etc. And none of that works.
Eventually we get desperate and start looking on the internet for solutions.
But ultimately, after we've been hurting for a few years, the question eventually comes up..."Why is this still hurting? Why does nothing help?"
It's a legit question: Why haven't you fixed your Tennis Elbow yet?
There's very specific reasons why you failed.
In short, the tools you were given were the wrong tools. It's not your fault they didn't work...mostly they don't work. Because they can't.
Why? Because Tennis Elbow is a flavor of Tendonitis, and tendonitis is a dynamic. A dynamic made up of multiple factors.
If the treatment you try doesn't effectively address each of the factors, then pain will eventually come back.
Anti-inflammatories at best lower inflammation levels (and thus pain levels) but totally ignore the causes of inflammation. Same with Corticosteroid Injections.
Rest (or changing jobs, or quitting playing guitar) just reduces new irritation to an already irritated dynamic.
Stretching only lengthens mobile tissue, not the tight non-mobile that needs to get targeted.
Etc.
For more on what it takes to get rid of tennis elbow symptoms, see the video below.
For more on Tennis Elbow, See: What Is Tennis Elbow? (Info that will actually make a difference.)