When your foot or heal hurts, you tend to baby it and not walk on that foot like normal, using the side or limping. Sometimes you should just walk normally so not to favor the pain area.
When you adjust your positions and walking, you put more stress on the other areas. You might put stress on one side of you back muscles by walking oddly and then feel back pain. You might lean oddly by favoring a painful shoulder. This might affect your neck or upper back muscles.
Your body works like a connected machine – when one part gets affected, it passes down to the next part to the next part. So, if you feel pain in your back, it might be from walking oddly, or holding you neck in a weird position.
It might be that you slept in a weird position and woke up in pain. Try to massage the area and then use it. Try not to baby the arm or shoulder or foot but use it normally.
If you did injure yourself, then ask your doctor if you need to baby it and stay off of it or should work it out by using it as normal. Sometimes you need to baby the area and use ice or heat for the pain until some recovery time allows you to use it as normally as you can.
To help yourself, keep doing the same strength building and stretching on both sides – if you use one arm, then do the same with the other. Make sure to balance your muscle work. Try not to baby the area by using the least resistance to pain.