I have been knitting for more than 10 years. My knitting tension is now not even. One side of my stitch is tighter than the other. This creates ladders on the tighter side and it shows as a vertical line on my knitting. Help!!!
Welcome to KH!
Is it with one particular yarn or have you seen this with different yarns?
See if this is due to the twist of the yarn.
http://knitty.com/ISSUEfall05/FEATwhyply.html
Can you post a photo of your knitting?
One thought- is the yarn loose enough as you are knitting from it? Sometimes we get so caught up in what we are doing that we are kind of yanking the yarn from the skein rather than having some surplus from which we knit.