I have pain radiating from my right shoulder down my arm, it’s so painful and happened pretty suddenly, I haven’t done anything that could possibly injure it. What could it be?

Update: i know you guys aren’t doctors but I’m not sure exactly what to do, this pain started in the right side of my neck radiating down my shoulder and arm to my elbow, now the right side of my chest has a dull ache, it started suddenly and that’s my concern, maybe if I had lifted something heavy or been feeling that all day I wouldn’t be as worried, I’m only 24 but have high stress and always have heart palpitations if that matters, I just don’t know if I should go to the hospital or not, I hate the thought of taking a bed someone might truly need, and my husband thinks I’m being a hypochondriac and is making me feel like I’m dumb, so I just have no support.