I Will Get Right To The Point. A Few Weeks

I will get right to the point. A few weeks ago I had a flu shot in my upper arm. Not sure if it was the right or left because I also had a tetanus done also. Anyway, since the shot occurred I have had consistent pain in the upper part of my arm just below my deltoid area. After having the pain for such a long time I was wondering if I had done something at work or maybe it was do to the flu shot. I then investigated it further and found that some people have actually had consistent pain since their flu shots. May I get your opinion on this matter.