My Nine Year Old Grandson Hd His Get First Flu

My nine year old grandson hd his get first flu shot today. He has had the naselndrops before. He is not running a fever and he is able to move his arm but it hurts to move it. He also had some sinus congestion before so wondering if this might have had something to do with it. We have have him ibuprofen but just worried about the arm pain. Thank you....