Are feelings of joy and a racing heart upon imagining touching a former female friend considered lust or a lack of affection?

Thoughts and imaginations are not necessarily lust, and one is not held accountable for inner thoughts as long as they do not lead to speech or action, as the Prophet (peace and blessings be upon him) said: "Indeed, Allah has forgiven my nation for whatever thoughts cross their minds, as long as they do not act upon them or speak of them."

However, one must not allow these thoughts to settle in the heart, as this may lead to falling into forbidden acts. One is held accountable for thoughts if they settle in the heart, because they are an action of the heart.

Ibn Hajar said: "One is held accountable for the actions of the heart if they become settled. As for his (peace and blessings be upon him) saying: 'Indeed, Allah has forgiven my nation for whatever thoughts cross their minds, as long as they do not speak of them or act upon them,' this is interpreted as referring to when they do not become settled."

The Hadith has clarified that thinking with the heart is a type of metaphorical fornication, because it is a means to it, as in the Hadith: "The heart yearns and wishes, and the private parts either confirm or deny that."