Dangers and threats, losing an advantage, relationship friction, duty and responsibility, increased pressure and ticking clocks

Being isolated in a remote location
Having no way to easily resupply food, water, medicine, etc. 
Being injured or becoming sick without a way to contact others for help 
A fire, flood, or enemy cutting the character off from allies
The character losing their ability to communicate with others (losing internet service, their phone breaking, losing power and being unable to charge their devices, etc.)
Being trapped in an elevator or cave-in
Being captured and imprisoned by enemy forces with no hope of rescue
The character being stranded in a remote location—e.g., marooned on an island or stuck in the mountains after a plane crash
Being caught behind enemy lines
Being separated from people who would intervene (an abuser isolating their spouse from friends or a royal family member being "kept safe" during a succession or coup)

Personal discomfort—being too hot, cold, wet, exposed, etc.
Having limited supplies
Being unable to see well (if lighting is an issue)
Lacking supplies to tend to injuries or minimize pain
Having to procure vital resources 
Being forced to travel by foot 
Navigating debris and hazards 
Not knowing what the dangers are in the area
Conditions that make navigation difficult (not having access to a GPS, fog making it impossible to see the stars, snipers monitoring a border, etc.)
Having to keep others calm (if the character is trapped with other people)
Arguments over what to do and how to get help