To have stiff shoulders; to feel tension or tightness in the neck/shoulder muscles.
長時間パソコンを使っていたら肩が凝ってしまった。
After using the computer for a long time, my shoulders became stiff.
マッサージを受けたら肩が凝りにくくなった。
After getting a massage, my shoulder stiffness became less frequent.
荷物を長く持っていたので肩が凝った。
Because I carried the luggage for a long time, my shoulders got stiff.
寒い日は血行が悪くなって肩が凝りやすい。
On cold days circulation worsens and shoulders are more likely to stiffen.
To feel ill at ease or tense; to feel uncomfortable or awkward in a situation.
初対面の人が多くて肩が凝った。
There were many people I was meeting for the first time, and I felt awkward/tense.
会議中に上司の意見と違って、説明している間ずっと肩が凝っていた。
I disagreed with my boss during the meeting, and I felt tense the whole time I was explaining.
あの映画は重苦しくて、観終わった後もしばらく肩が凝る感じがした。
That film was heavy; even after watching it I felt tense for a while.
Serious or sober (used prenominally to modify a noun; indicates a stiff or formal tone).
彼の話は肩が凝る話題ばかりで、場が和まなかった。
His conversation was all serious topics and it didn't lighten the mood.
肩が凝る式典が長時間続き、疲れてしまった。
The formal, stiff ceremony went on for a long time and I became tired.