I'm sorry you're worried sick, please realize there's no need to worry so. You are only five days post op.
Your leg endured major trauma. Your flesh was sliced, ligaments and muscles separated, hip possibly dislocated in an aggressive manner, bone sawed, then reamed out and a prosthetic hammered into place. You may experience varying degrees of stiffness for months to come. Sorry to be a bit graphic but given the description hopefully you will understand the stiffness, which is considered a form of pain.
What you need to do is take your meds on schedule so you're able to stay mobile and get up and walk for a few minutes every hour or two. Usually a trip to the bathroom, or kitchen to get a snack or beverage will suffice in these very early days.
You may not have made it through the Recovery Guidelines yet but take a peek at The Activity Progression For THR so you're staying sensibly active, without overdoing it.
https://bonesmart.org/forum/threads/activity-progression-for-thrs.13187/
Also, ice, ice, ice. It will help with pain and swelling. It's recommended you ice for 40-60 minutes, each session, several times per day.
Wishing you comfort as you begin the journey. We're here for you!
@Rdwolfe94