Small aircraft pilot reported cruising at the wrong altitude for direction of flight and while getting distracted by an overheating electronic; noticed another aircraft that was quite close in vertical distance.

Narrative

Was cruising at 4500 ft. on a east-southeast heading from ZZZ to Dane County (MSN). Was originally going to fly at 3500 ft. but hit a lot of chop; so decided to climb. For some reason; when I got to 4500 ft.; I leveled off thinking it was an appropriate altitude. I remained on this heading for about 5 - 10 minutes when my ForeFlight-equipped iPad alerted me that it was overheating. While looking for a place to put it to cool without sliding around the cabin; I caught motion out of the corner of my eye and saw a low-wing Aircraft Y at a fairly close distance. Had I been at 3500 ft. or 5500 ft.; the vertical distance would have been much greater. Had my ForeFlight been running leading up to the encounter; it would have alerted me of the aircraft; and that would have triggered me to question my altitude. If I had been on flight following; I would have gotten a call-out. Near miss was a result of me being at an incorrect altitude paired with not utilizing flight following. I don't believe Aircraft Y did anything incorrectly.