What Causes Right Sided Pain In The Shoulder?

Last October I was gardening for a day, mostly weeding, not heavy lifting or anything. Never felt anything strained. The next day I could not lift my right elbow outward to should height for the pain it brought. It took almost two weeks to regain that ability. The right shoulder/upper arm never completely recovered in that sleeping on that side was always uncomfortable and I ve been careful about what I lift, etc. since then. Now it s June and yesterday I had a very busy day setting up and hosting a large family event. I did not do any activity however that was out of the norm I ve been doing. I didn t notice any pain during the day but during the night the upper arm area nearest the shoulder was really sore and I didn t sleep well. Today the soreness is more pronounced and once again, raising my elbow out to the side and up toward my shoulder is very painful. Note: Raising the elbow forward so my hand can touch my shoulder does not produce the same pain. Is this just something that comes with age and I just need to give to time, an, or should I see someone about this.