Sorry, I missed your previous question. General anesthesia can cause many things. Muscle aches and pains after general anesthesia is a well known problem but it is usually temporary.
https://www.verywellhealth.com/general-anesthesia-side-effects-and-complications-4141168#:~:text=Anesthesia%20temporarily%20paralyzes%20your%20body,movements%20getting%20in%20the%20way.
Does your doctor think you have psoriatic arthritis or myopathy?

Even though psoriatic arthritis suggests a problem associated more with bones and joints it can also cause muscle pain just like PMR does.

Psoriatic arthritis and PMR are different but the symptoms are very similar. My guess is that there are many cases of psoriatic arthritis that are misdiagnosed as PMR and vice versa. PMR and psoriatic arthritis are difficult to differentiate even for experienced rheumatologists.

Embrel is often used to treat psoriatic arthritis but usually not recommended for PMR.
https://www.psoriasis.org/enbrel/
I hope this helps. Rheumatologists are smart people so you have to trust what they say. A wise rheumatologist will reevaluate over time as new information becomes available.