Neck and between-the-shoulder-blades pain??

[ny biker]

Also, in the past I've noticed more neck and shoulder pain during rides where I was very tense, such as long periods riding in traffic and having to have my hands on the brakes ready to stop at all times. So you might want to make sure you don't have a death grip on the bars.

[TrekTheKaty]

I agree with all of the above.

You may have just fatigued muscles that aren't used to that much work. My first hilly ride of the year left me with a knot between my shoulder blades that lasted several days.

You could have been tense--new route, longer ride, new riding partners.....

Or it could be a fit issue.

I would give it another try before making adjustments--unless it becomes more than "uncomfortable" and becomes "painful."

Have you tried stretching the area? Lying on one of those foam rollers or a tennis ball and trying to massage out?