Review of knee fluid drainage at Seo-gu Gyeongdaebon Orthopedic Clinic

I am someone who usually walks frequently and exercises by walking around the neighborhood or in the park. However, recently my knees have felt stiff and my legs feel swollen, and I have felt unnatural, so I visited an orthopedic clinic.
The director told me that there was a lot of fluid in my knee and that it needed to be drained. He brought a syringe and injected it into my knee to remove the fluid, and it hurt like hell. I teared up a little... He used a really thick needle, too.
Anyway, they drained the fluid with a syringe, gave me an injection with another, and prescribed medication. They told me to refrain from doing anything or exercising that puts strain on my knee for the time being. Ah... I feel so frustrated; I wonder how this will turn out...
Anyway, that was my review of visiting the hospital because of fluid buildup in my knee.
thank you