Go to a shop that will do the adjustments on the bike you have. Then do your usual ride and see if the knee pain goes away. If so, then try a few new bikes that they suggest. If the knee pain persists, its time to see an ortho doc.
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.