The simple answer: NO. The better answer: ABSOLUTELY NOT!! If a line of poetry ends at a natural point of pause, and is accompanied by punctuation (including commas, semi-colons or periods) then we call it an end-stopped line, and it can do wonderful things in a poem. For example, in Mark Doty's poem "The Embrace" the first and and last lines are end-stopped. You weren’t well or really ill yet either; just a little tired, your handsomeness tinged by grief or anticipation, which brought to your face a thoughtful, deepening grace. There are, as you can see, two lines in the stanza (the second and third) that are not end-stopped. We call this lines enjambed. Enjambed lines run right form one into the next; there is no natural pause. Instead, the lines would be read (in prose) with no pause. Why are there different kinds of lines? To create different effects! In the poem above, the two middle lines (which are enjambed) create movement in the poem, forcing the reader down the page more quickly, instead of allowing them to stop or pause. Other poets increase the number of enjambed lines in a row to create even more urgency. In the case of end-stopped lines at the end of this urgency, you are given the space to stop and consider what you have just read. Time to digest what the words mean. So, be thoughtful in where you break the line. Don't think you need punctuation or enjambment: instead, consider your choices! Because they impact the reader’s experience of the flow and motion of the poem, and how they will ultimately interpret the words!