Any change in a racquet can cause pain or ache just because the arm, hand, wrist, etc, are going to experience a change in torque, weight, stiffness, etc.
Also, you didn't mention string but that is often as big if not bigger factor as tension, string type, and an open or closed string pattern can create changes that cause pain or discomfort.
Dampeners, grips, and even ball type or court type can cause something if those are changes in your situation.
Answer: let yourself get some rest and then either go back to your old stick or make sure your string and other variables are the same as they were before the pain issue.
One other note: age is a big factor and quite frankly, you may have simply done something on a particular shot that strained something in your arm and playing is simply making that chronic inflamation noticiable.
Dave Smith: Author, Tennis Mastery/Coaching Mastery;
Senior Editor, TennisOne; Dunlop Master Professional