Hello,
This pressure or warm sensation can be due to anxiety, contact dermatitis, traumatic damage to the nerves of penis, diabetes, prostatitis, urethritis etc. Prostatitis is an inflammation of the prostate gland. From your symptoms, it can be due to chronic prostatitis. It is also possible that sitting on an inadequately padded surface or for prolonged periods of time is causing transient irritation to the prostate. This could be appearing as the pain in the penis.
You will need ultrasound, X-ray, and computerized tomography (CT) along with prostatic fluid examination along with prostate specific antigen.
I hope it helps. Take care and regards.
Oh forgot to add the tip looks slightly red, well to me my gf says otherwise. I feel it the most when I wake up but it seems to tone down as the day goes on and by the time I sleep it's hardly there. Is this an issue to go see a derm or a urologist?