Hi. My Husband (36 Yrs Old) Has Been Complaining About

Hi. My husband (36 yrs old) has been complaining about having discomfort with his neck/nape for quite some time. He says it feels stiff or sometimes painful so he tends to move it around. When I tried to massage his nape, I felt a hard immovable lump which becomes more apparent when he tilts his head down or to the left side. Location of the lump is around the hairline on the right side of his nape. The size is somewhat in between a pea and a grape. It is painless even when pressure is applied. Should we be worried?