Two weeks ago I had a kidney stone and went to the ER. I was fed morphine and something for nausea through an IV. Now my vein has hardened a few inches upstream of where the IV was and my arm is tender in the area of the hardened vein.
Should I be concered?
Is this normal?
Is this temporary?
Could you please hold your arm closer to the keyboard? 
Call your doctor’s office and ask a nurse this question. Far better than a message board diagnosis. If you don’t have a regular doctor, call the hospital where this procedure was done.
it sounds like a clot has formed.
if the pain is worrying you, get it checked.
BTBSTS
If someone told me this story, I would, after examining the person, likely attribute it to a bit of superficial phlebitis (not to be confused with the more sinister deep vein phlebitis/thrombosis). In other words, the vein is inflamed from the IV and will likely get better with mild analgesia and hot compresses.
However, in the absence of a proper history and physical, the possibility of a more serious condition could not be excluded.
So, in your case, I’d contact your doctor.
You’re getting follow-up care for you stones, right? Point this out to your provider----it sounds like a normal, temporary phelbitis----your tissue was peirced, irritating solutions (MS, Anzemet?, Reglan?, D5LR?) introduced into your vein and maybe a little leakage/ infiltration, all typical of IV therapy.
Cyn, RN