nagging
adj.adj. describing a feeling or thought that stays in your mind and will not go away. It is often used for a small but constant worry or a physical pain that does not stop.
adj. persistently annoying or distressing; used to describe a recurring thought, doubt, or physical sensation that is difficult to ignore. Often used as a participial adjective before a noun.
She has a nagging feeling that she forgot her keys.
Despite the doctor's reassurance, he couldn't shake the nagging doubt that something was seriously wrong.
The athlete struggled to maintain her focus during the final set, hampered by a nagging injury in her left ankle that had flared up during the warm-up.
Typically used attributively before nouns like 'doubt', 'feeling', 'pain', or 'worry'.