Drive chain replacement time, probably.

[flynrider]

Cycle Gear among others offers up inexpensive chain breaker and pinner.

What you don't want to do is lay out the old chain next to the new one and then cut as the old chain stretches; you want to count links.

Ideally what you want to do is get a chain with the correct number of links from the factory (then count the links). Fortunately, both of my CBs require 110 links, which is commonly available from most manufacturers. I haven't had to cut a new chain in many years.