I have recently rewatched the Iron Man movies, and I noticed something that bugged me. Towards the beginning of the first movie, Tony Stark is captured and imprisoned in a cave for quite some time (not sure how many days, but at least a couple). To get out, he has to build his own suit and fight his way out, etc, etc. This is fine in the context of the first movie. However in the context of the larger MCU, or at least the Iron Man part of it, this is weird.
In the second movie we learn that Howard Stark (Tony's dad) was a founder of S.H.I.E.L.D. which means they have known Tony probably his whole life, especially given his abilities which could (and do) prove to be very valuable to them. My question is, with the knowledge of Stark being in captivity, why did S.H.I.E.L.D. not act in the first movie? Had it not been for the work that the captors wanted Tony to do, he may not have escaped, and we wouldn't have Iron Man.
In-universe, why didn’t S.H.I.E.L.D. do anything?