Depending on how old you are may have a bearing on this. Also didn't mention if there was any pain or discomfort, just the sound/feeling..
A cracking/clicking sound may suggest you might need only a simple supplement like glucosamine. Some better supplements have glucosamine, chondroitin and MSM combined in one pill. When cold (in the morning) would also suggest a limited lubrication fluid, or even blood, in the area. Hopefully there is no arthritis in the family history. If a rotator cuff, pain would be present and perhaps a somewhat limited ROM. Some guy's have worked around a rotator cuff injury for years, though not advised.
Didn't say if these sound/feelings are present when working out, or any pain, so might be to your advantage to take a type of pill, as suggested above. Would also suggest keeping the area warm, even when working out. If problem doesn't seem to go away, and becomes worse, than it's time to get some medical advice. Good Luck.
Side Bar: some heavy lifters have gotten relief from deep tissue/sports massage, acupuncture, spinal adjustments, etc. Thought this tends to seem like a lack of lubrication fluid in the joint area.
