If the word you play in scrabble contains several smaller words, do you score all of them, or just the longest? E.g. TRAIN as TRAIN+RAIN+IN, or just TRAIN? Cannot find it clarified in any rules...
You only score each tile in a word once, where a word is the full sequence of letters added or modified in each column or row by your tile placement.
If you check the scoring example in the official rules from Hasbro (click on the Scoring tab, then scroll to the bottom), it will show you how it works.
The first word in their example is HORN which gives a total score of 14. This is reached by adding 4 points for H, plus one point each for O, R, & N for a subtotal of 7. Because it is the first word played, it is given a double word score bonus for a total of 14.
Note that there is no additional score for the O and R making a subword of OR.
This can also be seen in the second word placed where FARM only scores a 9 - the subwords of FAR and ARM cannot be counted as part of the total score.
Note that a tile you place that creates or modifies words on 2 or more columns or rows can be counted multiple times (as in turn 4 of the linked example where adding O & B creates three words - MOB, NOT, & BE) but this is the only way that a tile can be scored multiple times on the same turn.
The short answer is no.
The long answer is that you play a single word, the fact that there are other words contained in that word doesn't matter, there is only one word you created, the full and final word. If you did gain points for subwords, then pluralizing a word would gain you effectively double the score. (-1 for the s)
There are very rare cases where a tile creates multiple full legal words, if the tiles you placed in the word you are creating modify an existing word in a legal way (most commonly pluralization) then and only then do you score for multiple words in a turn.