Sourced from a great website for English idioms, The Idiom Connection:
A phrasal verb is a two-part or three-part verb and is sometimes called a compound verb. It is a combination of a verb and an adverb, a verb and a preposition, and a verb with an adverb and a preposition. It can have a literal meaning that is easy to understand because the meaning is clear from the words that are used. It can also have an idiomatic meaning which cannot easily be understood by looking at the words themselves.
to run around (something) – to run in a circle around something (literal meaning)
The dog ran around the tree.
to run around (somewhere) – to go to various places to do something (idiomatic meaning)
I spent the day running around downtown.
to run into (someone or something) – to hit or crash into someone or something (literal meaning)
The car ran into the truck on the busy street.
to run into (someone) – to meet someone by chance (idiomatic meaning)
I ran into my friend in a restaurant yesterday.
to run around with (someone) – to be friends and do things with someone or with a group of people (idiomatic meaning)
The boy is running around with a bad group of people.
Some idiomatic expressions are made with a phrasal verb plus some other words. These words are used in a fixed order to give an idiomatic meaning.
to run (verb) around (adverb) like a chicken with its head cut off – to run around with no purpose
I ran around like a chicken with its head cut off as I prepared for my holidays.