This article is purely conjecture. I have no hard data and would not even know how to create a study to test for it. BUT, I consider it biologically plausible. Tightness is a common sensation for people with pain and for athletes during training. However, when someone reports being tight in a region I find that they often are not in terms of their mobility. Their range of motion will be wonderful, perceptually their tissue will feel "loose" upon palpation (warning: highly subjective on my part) yet they report a sense of tightness. Main point being there are no objective signs of tightness or limits in their range of motion. So why does the perception of tightness occur?
Theories on the perception of tightness
1. that muscle that feels tight is actually beat up, pissed off, tired and angry with you. But it is just a muscle and has no vocabulary. It has no way to communicate complex emotions. Your muscle is my angry toddler. The muscle and always the nervous system just wants to communicate with you that something is off. It is overworked and wants a vacation. This is a good time to look at the synergists of the "tight" muscle and maybe see if they want to chip in when helping movement. or have someone speak with the nerves around the muscle and ask how they are feeling (cramped? hungry? needing fresh air?)
2. No reason a nerve isn't tight or tired or stressed. Check out the tension in your nervous system and then go Flossing (click here).
3. Generally irritated nervous system. A local issue is not necessarily a local problem. Think left arm pain with a heart attack. If you are in persistent pain than it is likely and normal to feel oddities through out your body.
4. I forget. There are definitely other possibilities. Discuss amongst yourselves.