Chest tightness on the night of ovulation is a very common phenomenon, but it can also be uncomfortable and worrying. This phenomenon usually occurs on the night of ovulation because changes in hormonal levels cause the oxygen levels in the atmosphere to drop, causing a feeling of chest tightness.

1. Oxygen levels in the atmosphere drop: During the night of ovulation, oxygen levels in the atmosphere at the Earth's surface usually drop. This is because as the sun rises and sets, the Earth's rotation causes the air to move, causing the oxygen content to change.

2. Changes in hormonal levels: On the night of ovulation, women’s hormonal levels will change, making them more sensitive and may feel chest tightness. This change in hormonal levels is usually most noticeable on the night of ovulation.

3. Psychological stress: Sometimes, chest tightness at night during ovulation may also be caused by psychological stress. For example, some people may feel anxious or nervous, and these emotions may also affect their atmosphere, causing a feeling of tightness in the chest.