Lesson 42: Concurrence with ながら あいだ うちに つつ
ながら states that two events are concurrently true. In the loose sense, they take place concurrently.
The left-hand event before ながら must be secondary to the event after ながら. The distinction is only intuitive, and affects what kinds of uses of ながら are acceptable. This sort of secondariness doesn't necessarily translate into english putting the left-hand event after a "while", it's just a tendency.
ながら attaches to the verb-sticky form of a verb.
読みながら眠ってしまう Ends up falling asleep while reading
ラテを飲みながら考える Thinks while drinking a latte.
ながら can not be used when the events have different subjects. In that case, あいだ/あいだに is used.
間/あいだ says that two events cover the same span of time. This places constraints on what sorts of statements it accepts. 間 itself acts like a noun.
食べる間、考える Thinking the whole time while eating
間に says that the event after 間に starts and ends within the span of time when the event before 間に is happening.
うちに says that an event happens while the statement before うちに is true, but generally instead of strictly. The statement before うちに is subject to various restrictions.
雨が降らないうちに帰ろう
Let's return while it's not raining (nuance: before it rains)
つつ, as in XつつY, is a formal-sounding "while" conjunction. Unlike many of the above, it just states that the events are concurrent, not which started when. Like ながら, the subject of both events must be the same.
Because つつ is formal, it is not normal to use it for everyday activities like "I am currently preparing breakfast". You can think of it like it implies that the events are special or occasional.
In general, つつ is an auxiliary conjunction that states that the left-hand event is in progress, and XつつY is just a use of it. In the pattern つつある, it states that the event is progressive, like one of the meanings of ている.