CHIAN ADJUSTMENT So

I'm very guilty of not adjusting my chain the entire time I've been riding - which is 2503 miles. I was looking over my bike and the chain is hanging low on the top and rubbing in to the chain guard. I don't have the time to get a replacement cotter pin to attempt adjusting it myself. So I have four questions: 1) How much should it cost for a shop to adjust my chain? 2) How does this compare to replacing the chain and sprockets? 3) How hard is it to adjust the chain yourself? The most important thing to me is being able to keep the alignment appropriately through the whole procedure. 4) What is the highest reliability chain (longest endurance) for a bike that rides a lot of highway miles. I described chain adjustment on my bike --http://totalmotorcycle.com/BBS/viewtopic.php?p=64704&highlight#64704,,