They’re not sitting comfortably, that’s exactly why they are trying to provoke a reaction - because economic sanctions are killing them.
The USA has, for once, made the sensible decision to use the main weapons they have - the control of the default currency and banking. Which is why Trump was persuaded to back away from a military response - and look implement additional sanctions.
The loss of the Triton cost the USA about $100M in assets, the additional sanctions will cost Iran a lot lot more......
https://www.cnn.com/2019/06/21/polit...ion/index.html