An engine stall mid-driving, mid-boating or worse yet mid-flight can certainly be a bad thing. Usually you'll find an electrical system issue that initiated the stall... and the engines won't fire until it's addressed.
When old injuries fail to get 100% better, or an illness persists much longer than anticipated, it's time to check your healing engines - and the first place to look should be your Nerve System. Nerves carry signals for muscle movement and sensation, but they also carry "neurotrophic" or tissue nourishing signals that influence growth and repair. Think of the person with limb atrophy from permanent nerve damage. Without proper nerve supply, body parts wither and die - the most common source of nerve flow restriction being a subluxated spine.
While there are many reasons for poor healing, nerve interference from spinal misalignments (subluxations) is a good place to start the trouble shooting process. Once normal nerve integrity and flow has been restored with proper adjustments, there's a good chance your healing engines will start back up you'll be on the road to recovery again.