I have been riding for about 6 months. Almost exclusively climbing, simply because of where I live. I took my bike in to have my shifter fixed and they told me my seat was too high. They measured my knee angle at 10 degrees and they said 30 degrees would be better. My first ride with the lower seat position proved uncomfortable. My lower back hurt and I felt weak in that position. I am 6'3" with slightly long legs. I naturally have more strength in my hamstrings than quads.

Should I give the lower seat position a chance? Or is it possible that my body will be better in the more agressive set up that I am used to?
Thanks.