It depends what you mean by, "Decompression Sickness." If you mean what divers call, "The Bends," then this should not happen due to taking off. Had you been SCUBA diving in the previous 24 hours? If you mean, "Altitude Sickness," then this is a different thing.
The fact that your colleagues did not suffer and you recognised the problem indicates that you do mean decompression sickness. However, to explain:
Decompression sickness happens when you have been pressurised and are breathing air under pressure (as you do when you are SCUBA diving). When you body is de-pressurised, small bubbles form in your blood stream. This is particularly painful in the joints, but can be lethal. That is why divers are trained not to fly within a certain period after immersions (the length of time is dependent on how many immersions; how deep you went, etc.)
Altitude sickness is different. It occurs when you breathe in air (oxygen) that is at too low a pressure. The result is that not enough oxygen gets to the brain. You suffer from Hypoxia. The bad thing about hypoxia is that you often do not realise that you are suffering from it. Normally, you will not die from this, unless exposed to a lack of oxygen for a long time. You will simply pass out, at which point (assuming you colleagues are still awake and not affected), they should realise that another of the crew is not well and take the necessary action.
So, in answer to you questions:
1. If it is decompression sickness, then you will continue to feel pain in the joints until you land (assuming you didn't feel pain beforehand). In the worst case scenario, you die from either an aneurysm or from the bubbles causing complications in the heart.
2. If it is altitude sickness, then you lose consciousness. If your colleagues take the proper precautions, you will awake again at about 8-12 thousand feet (possibly earlier, depending on the rate of descent).
3. If you go higher, and it is decompression sickness, the pain will get worse and the risk of fatal implications is higher.
4. If you go higher, and it is altitude sickness, you will still lose consciousness. It is unlikely that you will die or suffer any long-term effects, even at the operating ceiling of the C-130, unless you carry on flying for a long period of time.
In summary, altitude sickness should not be a problem (assuming that you are the only one affected). Decompression sickness is, potentially a problem. If you have been diving (or another situation 'under pressure'), you should leave a longer time between immersions and flying. Even the diving tables are worked out assuming a cabin pressure of about 8000 feet. If you go higher than that in an (even potentially) unpressurised aircraft, you need to leave a longer period to remove the nitrogen from the blood stream.
I would add that this is a very simplified version. Your flight surgeon will be able to tell you the real details.
The definition of a 'Pessimist': an Optimist with experience...