Only the muscle in red feel sore after pushups, why isn't my full chest feeling sore, what am I doing wrong?
welcome to Physical Fitness! I'm currently studying Kinesiology and Physical Education in university. Unfortunately, I can't say what exact exercises you've performed so I cannot give a specified answer or deduce why your exercise routine did not go the way you expected since your question is not super precise and detailed (e.g your goals, what exercises did you perform, how long was your exercise, etc.). Usually, muscles need to be worked past their threshold tolerance of a particular weight or load to be "sore" for a given amount of time. Perceived soreness essentially comes down to exercise-induced changes to the muscle's physiology (e.g inflammatory by-products) or physical damage (i.e. micro tearing of the muscle fibres). So, perhaps you need to reevaluate your pushup techniques, choose another exercise to do, add more volume, more load, or change up your usual routine altogether. Our chest muscles are generally categorized as the pectoralis major and minor (with certain neck muscles and a small muscle contributing). Can't say what you want to accomplish as a "full chest" workout since those are just the muscle involved. However, if you consider the chest as a part of the core (which it is) and what you meant by "full chest", I'd recommend you workout out the entire core (torso, for informal understandings).
There is quite a bit more exercise physiology tips and anatomical issues related that I could add. I see you have a winged scapula from the comments. Perhaps check with your Physiotherapist or Chiropractor (NOT PHYSICIAN - they are not as specialized in the workings of the musculoskeletal system). Winged scapulas could interfere with your pushups as the abnormal position of the scapula affects the position of our shoulders, which can translate to altered pushup technique. This is called a "kinetic chain" - one issue in some area can affect other areas as these areas all work together. Hope this helps :)
About the push-ups, you probably shouldn't worry too much, as soreness does not necessarily indicate progress and the inner and outer chest are essentially the same muscle regardless. I personally notice that my chest soreness is pretty unpredictable, but I make regular (and balanced) progress in size and strength anyway.
As for the winged scapula, I'm no physical therapist, but muscle imbalances usually seems to contribute to issues like this. If you aren't already, try doing just as many exercises for your back and external rotators as for your chest. Hope this helps!