Indeed I'm in the US. Actually its hard to tell what the cost would be. It might be just $500 if they don't admit me. But it could be thousands. No way to know without actually going.
To be clear I don't have symptoms right now that warrant it and highly unlikely its J&J related anyway. But nevertheless we do have to consider costs here before we make any decisions involving hospitals.
Seems that you live in North America. It is utterly bewildering that people are expected to make this determination.
I can go to the ER whenever I suspect a serious problem, to the ultimate cost of... 5 euros. That's the limit. Post-occupation EU backwater country.