How can I get a single row on a inner join not to double my sum
You could use multiple SELECT Statements, like this:

SELECT CHT.ID,
   (SELECT SUM(TOTAL_E + TOTAL_F + TOTAL_STOC) 
   FROM DEP_DEZ WHERE FK_ID_CHESTIONAR = cht.ID),
   (SELECT SUM(MASA_TOTALA) FROM CAR_EXP WHERE FK_ID_CHESTIONAR = CHT.ID)
   FROM CHEST cht
GROUP BY CHT.ID