Where specifically and what type specifically of pain is it? You said the whole penis area hurts, and you said the left side hurts. Is it your testicles? Spermatic cords? Ligaments? Tunica? Corpora? Glans? Skin? Urethra? Exterior blood vessels?
When I first began PE I experienced regular pain in my left spermatic cord from the stretching of the newbie routine. It lasted several months and was aggravated by almost every workout. Eventually when I first tried hanging I felt a release, as though it had been stretched out sufficiently, and it did not bother me again after that.
Despite that success story, there have been several threads I’ve seen over the years of guys in a similar situation to you - non-specific pain from starting PE that has no medical or physical basis. Some of them end up banging their heads against the wall and it becomes a permanent problem for them which they battle for years to great detriment of their sex lives. So are you doomed to never do PE? Maybe.
I endured a pain syndrome for about 5 years due to a repetitive motion / overuse sports injury, and in overcoming that I learned that pain can be very mental. Long after my injury had physically healed, programs in the way my brain interpreted signals from the joint were causing the perception of pain from normal activity. Even beyond the mind, these programs can exist in the sensory and motor nervous system out in the body. The mind and nerves themselves had to trained to stop running this pain program.
Anyway, point is that pain doesn’t necessarily have a physical basis, or rather it’s physical basis can be a very small part of the total experience. If you’ve ever watched a child take a minor bump, and erupt into a big emotional reaction as if somebody had cut their arm off, that’s another example. Sometimes these reactions are wired so strangely and deeply into the tissues and brain that they seem 100% real, and they are real, as real as any perception.
PE involves a certain level of discomfort - all the above listed tissues are taking stresses that aren’t normally encountered. My theory on most of the non-specific pain threads that get posted is that these new stresses on the genital tissues are being subconsciously interpreted as damage to the tissues, which then starts a chain reaction leading to these long threads where nobody can provide any help and doctors can’t find anything physically wrong.
So that was a long winded way of saying: Try relaxing deeply for your workouts, don't be tight, and let the tissues fully relax. Then after the workout if there is any pain you could try massaging the area while relaxing, and mentally interpreting it as post workout soreness rather than damage.
All that said, I will re-iterate some guys with this issue never get past it (for whatever reason, my theory could be totally wrong) and you are already good size. So maybe your initial inclination and Titleist are correct: PE may not be for you.
