Recently my right shoulder and upper arm has been aching and feeling weak / discomforting. should i be concerned?

Right shoulder pain: Do you play sports. baseball? pitch? Lift heavy items? overhead lifting? These can affect your shoulder , you are young for cervical spine disease. Would try resting the shoulder for a few days , ice 10 minutes on 3-4 times a day, if not allergic try motrin 200 mg -2 tabs 3 x a day . Follow up with doctor/urgent care could be rotator cuff, labral tear , bursitis

Yes: If you are experiencing weakness as well as discomfort, then you should get checked.