differences between a sign and a symptom

Describe the differences between a sign and a symptom. Give additional examples of signs that can be observed and then discuss the difference of symptoms that only the patient can describe. What are the four vital signs that are used to show evidence of disease? Why are both types of observation important in determining proper medical treatment? Why is it difficult to evaluate a symptom such as pain?

https://www.youtube.com/watch?v=cHdSJNFj2wY watch this video for a brief description of the difference between sign vs symptom
https://www.youtube.com/watch?v=N6aJTDUab_0 watch this video for a brief description of the four vital signs used to show evidence of disease
https://www.youtube.com/watch?v=Uo9zwOn-he8 watch this video on how to conduct a pain assessment