Early 30s, this year I had knee pain every time I when for a jog, the pain lasted 2 or 3 days each time, it lasted for over a month until I met with my brother who's a physiotherapist and gave me very simple advice:

• warm up before running
• run in smaller steps, large steps are harder on the knees
• stop or take a break before it starts hurting
• run more often, 3 times per week minimum

The pain was gone in 2~3 weeks. Has not came back since.

It's not always about the age, sometimes it's about doing things correctly or getting the right care.