Pain in the Big Toe. Gout is a notorious cause of sudden pain in the big toe joint, along with redness and swelling (seen here). Osteoarthritis is another culprit that causes pain and swelling. If the joint is rigid, it may be hallux rigidus, a complication of arthritis where a bone spur develops.
But to see it more clearly: scientific observation is to view  the movements, and effects of those movements, or to view any  situation, and the effect of it.   Example: I saw a fish swim though the water. So based on what I  observed, I ask questions, like, how did the fish swim though the  water.
My formal (but open to improvement) definition of 'science': A science is a method, a set of rules using fact and logic, for evidence gathering and testing truth claims in a given field of inquiry, rules which are publicly usable (i.e., neutrally applied to all participants), and which can reasonably be said to lead to the truth of that particular area.