Hello,
I think the current problem with your arm,
stiffness is due to driving for long periods. You need
magnesium and vitamin-B supplement. Plus, if the arm is exposed to the sun, it might be suffer sun burning although minor. Should apply sunscreen cream before you expose to sun and during the day.
If it is possible, you can have some rest, not driving for some time until you will feel better. Meanwhile, physiotherapy/
massage with essential oils can also relieve stiffness. But remember to evaluate for sunburning and treating adequately.
Hydrocortisone cream might not help, especially if exposed to the sun. You need anti-inflammatory cream, plus sunscreen cream.
All the best. Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. Albana Sejdini, General & Family Physician