What Causes A Lump With Severe Headaches?

hi 4 days ago i crashed my mtn bike, wearing helmet.
ct neg 2 nights ago

take pain meds regularly from hx from spine and brain surgery but headaches are still severe and this morning i awoke with a lump on part of my head that has hurt more than other places and it feels sort of squishy and hard...

i'm still having nausea (vomited first 2 days after fall).

should I return to ER for lump and that the headaches are much much worse when upright? some nausea still but headache and lump are making me nervous.

pupils are fine, balance is fine.

thanks