No: frittata, passata, fiammabile, staccato, there are many words with double consonants where the stress is on the next syllable. Double consonants really do count double, though: they are longer (ss, mm) where possible, or they introduce a slight pause (pp, bb, cc) where not. This lengthening is what gives Italian its lovely lilting quality, compare it with the machine-gun rhythms of Spanish. Google 'gemination' (literally: twinning) for more information.