Well... it could be a ganglion (where the tendon sheath gets a bubble in it filled with serum {the fluid of the body}), a lipoma (kind of soft and rolly-polly), calcification where one of the shoulder tendons attaches... Cannot think of much else it could be.
the pelvic bone and the top of the femur bone. also your shoulder and the top of your arm bone.
The bone at the top of the arm is called the humerus. It is the long bone that runs from the shoulder to the elbow.
bone marrow
i pitched in baseball for a couple of years, and my shoulder does the same thing. On my right shoulder, the bone feels loose, but there is no pain.
The shoulder consists of your acromion, clavicle, scapular and the top of your humerus
Clavicle
The clavicle is also commonly called the "collar bone." It stretches between the shoulder and the neck. The cervical vertebrae are the top of the spine: the are the first seven vertebrae going from the top of the spine down. The scapula is commonly called the "shoulder blade" and is a large, flat bone at the top of the back.
Hamstring Knee Shoulder Ankle Collar Bone
A tendon is the continuation of a muscle as it attaches to a bone. It runs from the back of the shoulder blade and attaches to the top of the arm bone.
There are two that a person might feel. One in the front called the clavicle (collar bone) and a large flat one on the back of the shoulder called the scapula.
The bone that runs across the top of the chest between the shoulders is the clavicle, commonly known as the collarbone. It connects the shoulder blade to the sternum (breastbone) and helps to support the arm and shoulder.
I don't know, I am wondering the exact same thing because I have the same condition. I have popping and grinding sounds when I rotate my arm. No real pain though. Just tight, and loss of flexibility The bone on top of my left shoulder sticks up higher than the bone on my top right shoulder. My mom thinks it from prolonged activity from playing the drums. Its either build up calcium deposits, or the cushioning has deteriorated.