I had this same problem last summer, pain in the chest and left arm within minutes of starting a run. On visiting my GP I was rushed to hospital, after tests the diagnosis was angina and mild COPD (85% lung function)
The consultant in the hospital was very supportive. In the main it was my diet and high cholesterol that were causing the problem. I rarely eat meat and did eat a lot of dairy products (I ate a lot of cheese). A course of tablets to lower the cholesterol and a change of diet has got rid of the problem. COPD cannot be cured but a new inhaler which includes a lose dose steroid really helps. I am now back running better than I have for a few years. The consultant (also a runner) did tell me it was probably the fact I had been running for over 30 years that helped me get through.
Guess we are lucky in the north east in that we can visit Start Fitness. Even on new models their prices are hard to beat. Also happy to support them as they sponsor races in the north east including the cross country league, there staff tend to be all runners who give good advice.
The online prices also tend to be the same as the shop prices. I recently bought Asics GT-2000 in grey and orange (last years colours) for £57.
You did not state where you live but have a look at at the Pier to Pier race organised by my club, Sunderland Strollers and South Shields Harriers. Takes place in May and has built up a good reputation amongst local runners.
Don't get me wrong I love my Parkruns and you are to be applauded for your efforts but I would question whether South Tyneside could support another Parkrun. There are already 6 parkruns in the Tyne and Wear area and any run would have to provide something different to what is already in place. South Shields started earlier this year and the numbers average 80 per week but South Shields is slightly different in that it not really in a park and does use the same finish line as the GNR.