Visually inspect the chain—is it as dry as a bone, rusty or kinked? Is the free play correct? Is it centered on the rear sprocket? Chains that are biased to one side or the other of the sprocket indicate alignment problems. Consult your shop manual for the correct free play and adjustment procedure.
Preferably a chain should be lubricated when you return from a ride; the chain is nice and warm then, and the lubricant tends to flow into the nooks and crannies more readily. Jab the extender straw into the inside run of the chain; that way centrifugal force will help distribute the goo. There are four areas that require lubrication: the area between the chain's connecting links or side plates, both inner (the side facing the wheel) and outer, and the chain rollers, again inner and outer.